3 letters:
ure

4 letters:
doer, poor

5 letters:
amour, coeur

6 letters:
auteur, colure, immure, parure, undoer, velour, velure, voyeur, you're

7 letters:
hauteur, pasteur

8 letters:
frotteur, grandeur

9 letters:
raconteur

10 letters:
de rigueur

13 letters:
force majeure, louis pasteur

21 letters:
delusions of grandeur

1 letter:
r

2 letters:
ar, er, or, r.

3 letters:
air, are, ayr, bar, bur, car, cur, ear, err, far, fir, for, fur, gar, ire, jar, mar, mir, nor, npr, oar, ore, par, per, sir, tar, tor, war

4 letters:
abor, adar, amir, bare, barr, bear, beer, bier, birr, blur, boar, boer, boor, bore, burr, care, carr, char, core, cure, czar, dare, dear, deer, dire, door, dour, emir, fahr, fair, fare, fear, fehr, fire, fore, four, gear, gere, gore, hair, hare, hear, heir, here, herr, hire, hoar, hour, igor, jeer, jour, lair, lear, lohr, lore, lour, lure, lyre, mare, meir, mere, mire, moor, more, near, pair, pare, parr, pear, peer, pier, pore, pour, pure, purr, rare, rear, roar, ruhr, scar, sear, seer, sere, slur, soar, sore, sour, spar, spur, star, stir, sure, tear, thor, tier, tore, torr, tour, tsar, tyre, veer, voir, ware, wear, weir, were, wire, wore, year, yore, your

5 letters:
abhor, adore, afire, asarh, ashir, assur, astir, athar, aware, babar, barre, bazar, bihar, blair, blare, blear, chair, cheer, chirr, chore, churr, cigar, clear, corps, crore, dakar, damar, debar, decor, defer, demur, deter, dinar, dower, drear, flair, flare, floor, flour, freyr, glare, greer, grier, incur, infer, inter, inure, kotar, lamar, loire, maher, moire, moore, murre, myrrh, ne'er, occur, qatar, queer, quire, recur, refer, safar, sapir, scare, score, scour, selar, senor, share, shear, sheer, sherr, shire, shirr, shore, sitar, smear, snare, sneer, snore, spare, spear, spire, spoor, spore, stair, stare, starr, steer, store, swear, swore, their, there, vanir, vidar, we're, where, whirr, whore, yasir, zaire

6 letters:
abjure, adhere, adjure, admire, affair, aflare, allure, anshar, appear, ashore, aspire, assure, bazaar, before, beware, bonior, by far, career, claire, cohere, concur, confer, cottar, demure, detour, devoir, disbar, drawer, eclair, endear, endure, ensure, exmoor, expire, fakeer, galore, go far, go for, guitar, ignore, impair, impure, inhere, insure, isobar, jamjar, kaffir, lenore, lontar, manure, mature, menhir, midair, nuphar, o'hare, pierre, pindar, poseur, prayer, prefer, prewar, rehear, repair, retire, revere, rigour, safire, salvor, sambar, sambur, schorr, secpar, secure, severe, shamir, shmear, so far, sphere, square, squire, unfair, unsure, vapour, veneer, vigour

7 letters:
affaire, anymore, ask for, astaire, austere, au pair, besmear, big sur, bizarre, bonaire, bonheur, bugbear, cashier, co-star, compare, compeer, compere, cooccur, couture, cry for, danseur, declare, deplore, despair, de jure, ensnare, explore, flexure, forbear, gravure, guinier, hachure, hot air, hot war, houhere, implore, inquire, inshore, inspire, kildeer, languor, liqueur, minibar, moliere, myanmar, nervure, not far, no more, nut bar, obscure, on tour, opt for, outroar, pay for, pioneer, postwar, premier, prepare, procure, pry bar, rancour, rapport, require, respire, restore, run for, samovar, schmear, shophar, sincere, soilure, succour, tangier, tarsier, they're, tonsure, try for, tussore, tv star, unaware, unclear, upstair, up here, vitharr, wafture, wet bar, who are, you are

8 letters:
a. t. r., abampere, abattoir, allosaur, amanpour, ant bear, axle bar, baccilar, barosaur, bell jar, blue air, boer war, bog star, brochure, brumaire, bus fare, c. p. r., cab fare, call for, calm air, care for, car care, car door, cash bar, cat bear, cavalier, coal car, coal tar, coiffeur, coiffure, coinsure, cold war, date bar, day care, debonair, derriere, dog star, domineer, done for, due care, elaphure, encolure, engineer, ex-mayor, f. d. r., fall for, feel for, fend for, footgear, footsure, forswear, for sure, frontier, gill bar, give ear, got your, grab bar, grimoire, handwear, high bar, hot-wire, ice bear, immature, iron ore, killdeer, lavalier, lead ore, longueur, look for, low gear, mail car, make for, markhoor, microbar, milk bar, monsieur, muleteer, mutineer, nightjar, offshore, open-air, open air, outscore, overbear, overhear, p. c. r., pace car, paramour, parterre, peignoir, perspire, per year, pine tar, premiere, put your, r. j. r., race car, reappear, reassure, red deer, reinsure, roe deer, saboteur, sand bar, scimitar, sea hare, sea star, seigneur, send for, sinecure, slop jar, souvenir, sun gear, t-square, take for, tamanoir, tank car, testiere, thus far, transfer, true fir, twoscore, v. c. r., voltaire, voussoir, what are, what for, wheatear, wirehair, wood tar

9 letters:
air corps, allow for, all clear, apatosaur, archosaur, au revoir, back door, balladeer, bandoleer, bandolier, barn door, basketeer, belvedere, blue star, bock beer, brigadier, buccaneer, cabin car, cable car, cafe noir, candy bar, cannoneer, cared-for, carob bar, chair car, chauffeur, chevalier, chinaware, civil war, class war, cold sore, color bar, come near, coon bear, cover for, dark beer, debonaire, disappear, disrepair, downstair, draw near, duty tour, each year, film star, financier, fire door, fourscore, fruit bar, gadgeteer, gazetteer, giant fir, give care, gondolier, go to war, grand fir, great war, grope for, guarantor, guinevere, gum myrrh, hadrosaur, hair care, half door, hekmatyar, held dear, high gear, hold dear, holy year, hoped-for, horsehair, inner ear, insincere, interfere, in so far, joint fir, kala-azar, leap year, life peer, light air, make pure, make sure, mason jar, megathere, metal bar, mouse ear, mule deer, musketeer, musk deer, near beer, next door, nothosaur, once more, open door, outer ear, over here, pap smear, persevere, pinch bar, pistoleer, plump for, plunk for, premature, presbyter, price war, privateer, profiteer, prowl car, pterosaur, puppeteer, pushchair, quest for, racketeer, red scare, rest-cure, rock star, root beer, root hair, salad bar, scout car, set afire, shoot for, side door, sightseer, skin care, slice bar, sloganeer, snack bar, solitaire, sonneteer, sorry for, space bar, speak for, sport car, spur gear, squad car, stall bar, stand for, stegosaur, stock car, stud mare, superstar, sushi bar, sweep oar, take care, taxi fare, that your, there are, towel bar, trap door, trochlear, volunteer, warrantor, wasteweir, where are, white fir, wild boar, world war, worm gear

10 letters:
air-to-air, alpine fir, ankylosaur, answer for, auctioneer, balsam fir, bath chair, baudelaire, bear's ear, belshazzar, bevel gear, birch beer, blackamoor, black bear, bombardier, brontosaur, brown bear, budget for, buffet car, bumper car, burro deer, called for, camp chair, carabineer, cattle car, ceratosaur, chandelier, charioteer, child care, civil year, cockleburr, coffee bar, commandeer, cookie jar, cross hair, debonnaire, deck chair, dining car, double bar, dutch door, easy chair, embouchure, escritoire, estate car, every year, faith cure, false hair, first gear, fixed star, flare star, foursquare, fraser fir, front door, giant star, god of war, gondoliere, grand tour, great bear, great care, great year, ground fir, guard hair, halberdier, harpooneer, heavy spar, heretofore, honey bear, ictodosaur, in one ear, in the air, jaunty car, kieselguhr, koala bear, korean war, lawn chair, leyden jar, light beer, light year, liquid air, longed-for, looked-for, louis d'or, lunar year, mal de mer, man-of-war, marsh hare, mens store, middle ear, mouse deer, mouse hare, movie star, north star, opera star, oregon fir, oyster bar, palace car, panda bear, parlor car, patrol car, peanut bar, pelycosaur, petit four, pinot noir, plesiosaur, polar bear, polar hare, polar star, police car, pubic hair, racing car, re-explore, river pear, scotch fir, scrutineer, secretaire, seismosaur, set ashore, set square, shoe store, shop floor, side chair, silver fir, skunk bear, sloth bear, small beer, smoothbore, solar year, sports car, stage door, swamp hare, swing door, teddy bear, texas star, third gear, threescore, tidal bore, to be sure, to one ear, track star, train fare, trojan war, try square, tug-of-war, uintathere, underscore, water deer, weiss beer, wing chair, wished-for, woody pear

11 letters:
account for, apgar score, apricot bar, arctic char, arctic hare, baggage car, balsam pear, basket star, beach chair, billionaire, binary star, black maire, bronx cheer, bronze star, buffalo bur, camera care, candidature, candy store, church year, come before, come in for, common year, compact car, connoisseur, corythosaur, crimean war, cry out for, dance floor, death chair, dental care, doctrinaire, double door, double star, douglas fir, dressed ore, dromaeosaur, dyaus-pitar, edward lear, fallow deer, first floor, fiscal year, flying mare, freight car, french door, gala affair, ginger beer, golden star, gomphothere, gondola car, granola bar, health care, hershey bar, ichthyosaur, iraqi dinar, kodiak bear, limited war, liquidambar, litterateur, little bear, looking for, love affair, lowland fir, mexican war, milliampere, millionaire, mineral tar, munich beer, native bear, native pear, ocean floor, pamphleteer, parlour car, peace corps, peacock ore, planet gear, potty chair, prepare for, press corps, provide for, puff of air, pullman car, railway car, ripping bar, rotogravure, saddle sore, schenk beer, school year, screen door, seckel pear, second gear, sedan chair, silver star, six day war, slight care, smoking car, solar flare, spanish war, spruce beer, squeeze for, stable gear, styracosaur, subway fare, supersedure, syrian bear, take a dare, that you're, touring car, trolley car, tyrannosaur, ulaanbaatar, uncared-for, unhoped-for, uranium ore, vanity fair, vietnam war, volt-ampere, walk on air, what's your, what you're, white maire, wicket door, woolly bear, word square, yacht chair, yearned-for

12 letters:
aide-memoire, anchovy pear, avocado pear, barber chair, barking deer, bartle frere, belgian hare, bevel square, bill of fare, blazing star, brittle star, buffer store, camel's hair, ceramic ware, colorado fir, electric car, elephant ear, elevator car, entrepreneur, evening star, external ear, far and near, feather star, fishing gear, flower store, folding door, garden chair, going ashore, green manure, grizzly bear, ground floor, head of hair, heliogravure, hitching bar, iceland spar, internal ear, in disrepair, king's spear, kuala lumpur, landing gear, latin square, leisure wear, libyan dinar, liquor store, lounge chair, magic square, marine corps, marston moor, medical care, morning star, morris chair, neutron star, nursing care, outside door, photogravure, pied-a-terre, powder store, prairie star, prickly pear, psittacosaur, railroad car, restaurateur, retail store, savoir-faire, sensory hair, serpent star, service door, sleeping car, sliding door, sloop of war, soup du jour, standing for, state of war, staurikosaur, steel guitar, swivel chair, that you are, times square, time of year, uncalled-for, unlooked-for, unwished-for, varying hare, vina del mar, what is more, white squire, without fear, wrecking bar, yemeni dinar

13 letters:
academic year, and there are, army engineer, bahrain dinar, bartlett pear, bowling score, bring to bear, calendar year, carte du jour, chocolate bar, cinnamon bear, conservatoire, conventioneer, cote d'ivoire, country store, crystal clear, devil's cigar, european hare, exterior door, feeding chair, folding chair, general store, grocery store, haute couture, hospital care, interior door, iranian dinar, japanese deer, jewelry store, kangaroo bear, kangaroo hare, kuwaiti dinar, laissez-faire, laissez faire, last frontier, lord's prayer, market square, more and more, multiple star, musical score, nom de guerre, operatic star, ordinary care, oriental sore, package store, parquet floor, passenger car, platonic year, porte-cochere, porter's beer, public square, questionnaire, rocking chair, rouge et noir, shooting star, snowshoe hare, social affair, steering gear, stinging hair, swinging door, tropical sore, tropical year, variable star, virginia deer, wear and tear, windsor chair, woodland star

14 letters:
accordion door, algerian dinar, alligator pear, baseball score, cervical smear, christian year, christmas star, civil engineer, clothing store, coffee liqueur, commissionaire, compressed air, computer store, concessionaire, discount store, electric chair, elephant's ear, evening prayer, financial year, football score, greenland spar, hardware store, hold still for, horizontal bar, know the score, legal transfer, morning prayer, naval engineer, nonsmoking car, orange liqueur, planetary gear, pneumatic tyre, red dwarf star, red silver fir, straight chair, surface-to-air, take the floor, tunisian dinar, walking on air, warning of war, war to end war, whitetail deer, white lead ore, world premiere, yom kippur war

15 letters:
acoustic guitar, black marketeer, captain's chair, cauliflower ear, croix de guerre, earthenware jar, electric guitar, esprit de corps, first world war, flight engineer, have been there, hawaiian guitar, house of prayer, jewish new year, jordanian dinar, kilovolt-ampere, marine engineer, mezzanine floor, mining engineer, out of thin air, prisoner of war, reasonable care, reclining chair, responsible for, sabbatical year, santa lucia fir, specialty store, television star, us marine corps, with great care

16 letters:
basketball score, capital of qatar, capital of zaire, celestial sphere, come to the fore, department store, diplomatic corps, highway engineer, on a lower floor, pachycephalosaur, pays de la loire, persian gulf war, political sphere, refrigerator car, second world war, secretary of war, seven years' war, step to the fore, white dwarf star

17 letters:
astronomical year, brace oneself for, castle in the air, convenience store, differential gear, earning per share, english civil war, green douglas fir, implements of war, little chief hare, lowland white fir, military engineer, on a higher floor, overstuffed chair, peloponnesian war, pere david's deer, railroad engineer, software engineer, thirty years' war, yugoslavian dinar

18 letters:
aerospace engineer, alaskan brown bear, american civil war, carpenter's square, dense blazing star, haberdashery store, hundred years' war, military volunteer, pacific silver fir, russo-japanese war, tender loving care

19 letters:
american black bear, automotive engineer, efficiency engineer, elasticity of shear, electrical engineer, european silver fir, franco-prussian war, mechanical engineer

20 letters:
california white fir, pinion and ring gear, vestibule of the ear

21 letters:
aeronautical engineer, book of common prayer, building supply store, french and indian war, inspection and repair, southern yemeni dinar

22 letters:
battle of marston moor, metallurgical engineer, privilege of the floor

31 letters:
reserve officers training corps