2 letters:
or, er

3 letters:
bur, mir, for, air, fur, war, err, oar, ore, ear, ayr, tor, sir, ire, cur, nor, per, fir

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

5 letters:
khmer, score, loire, aware, blair, moore, assur, whore, crore, churr, queer, snore, skier, glare, blare, ameer, drear, ne'er, whirr, flair, chore, scour, defer, cheer, flare, afire, store, amour, spore, dower, senor, demur, steer, corps, share, shirr, stair, we're, there, snare, chirr, stare, inure, shore, floor, myrrh, spear, their, sneer, inter, quire, shear, swear, adore, spare, abhor, incur, shire, sheer, chair, flour, zaire, spoor, occur, refer, scare, blear, clear, moire, infer, deter, spire, smear, decor, murre, swore, recur, where, ashir, astir, freyr, greer, grier, sapir, sherr, vanir, yasir

6 letters:
appear, unfair, impure, secure, velour, impair, insure, drawer, career, confer, sphere, midair, ensure, affair, assure, square, immure, aspire, adjure, galore, pierre, vigour, endear, unsure, endure, ignore, squire, retire, beware, concur, rehear, repair, prayer, tumour, cohere, valour, severe, claire, prewar, detour, mature, before, poseur, ashore, vapour, prefer, manure, you're, veneer, demure, revere, adhere, savour, voyeur, allure, admire, expire, abjure, aflare, eclair, exmoor, fakeer, inhere, kaffir, lenore, menhir, o'hare, pindar, rigour, safire, salvor, sambur, schorr, shamir, shmear

7 letters:
austere, compere, verdure, respire, rapport, pasteur, compare, unclear, inshore, liqueur, premier, anymore, prepare, schmear, require, deplore, pioneer, they're, inquire, postwar, saviour, masseur, cashier, inspire, sincere, restore, couture, ensnare, declare, compeer, danseur, succour, obscure, unaware, fervour, procure, explore, flavour, affaire, despair, implore, astaire, besmear, bonaire, bonheur, bugbear, cooccur, flexure, forbear, gravure, guinier, hachure, houhere, kildeer, languor, moliere, nervure, outroar, rancour, soilure, tangier, tarsier, tonsure, tussore, upstair, wafture

8 letters:
brochure, overhear, polypore, reappear, brumaire, engineer, reinsure, seigneur, souvenir, cavalier, offshore, saboteur, mutineer, frontier, frotteur, grandeur, immature, domineer, frimaire, voltaire, monsieur, reassure, debonair, forswear, premiere, perspire, transfer, abampere, allosaur, amanpour, barosaur, coiffeur, coiffure, coinsure, derriere, elaphure, encolure, ex-mayor, footgear, footsure, handwear, hot-wire, killdeer, lavalier, longueur, markhoor, muleteer, open-air, outscore, overbear, paramour, parterre, sinecure, t-square, tamanoir, testiere, twoscore, wheatear, wirehair

9 letters:
balladeer, guarantor, buccaneer, puppeteer, chevalier, raconteur, disappear, solitaire, insincere, musketeer, persevere, premature, gondolier, volunteer, profiteer, disrepair, interfere, bandolier, racketeer, sightseer, chauffeur, financier, brigadier, belvedere, apatosaur, archosaur, bandoleer, basketeer, cannoneer, cared-for, chinaware, debonaire, downstair, fourscore, gadgeteer, gazetteer, guinevere, hadrosaur, hoped-for, horsehair, megathere, nothosaur, pistoleer, presbyter, privateer, pterosaur, pushchair, rest-cure, sloganeer, sonneteer, stegosaur, trochlear, warrantor, wasteweir

10 letters:
quadrature, bombardier, chandelier, charioteer, commandeer, foursquare, underscore, heretofore, auctioneer, air-to-air, ankylosaur, baudelaire, blackamoor, brontosaur, carabineer, ceratosaur, cockleburr, debonnaire, embouchure, gondoliere, halberdier, harpooneer, ictodosaur, kieselguhr, longed-for, looked-for, man-of-war, pelycosaur, plesiosaur, re-explore, scrutineer, secretaire, seismosaur, smoothbore, threescore, tug-of-war, uintathere, wished-for

11 letters:
pamphleteer, uncared-for, billionaire, litterateur, doctrinaire, millionaire, connoisseur, rectilinear, ichthyosaur, interlinear, candidature, corythosaur, dromaeosaur, gomphothere, milliampere, rotogravure, styracosaur, supersedure, tyrannosaur, unhoped-for, volt-ampere, yearned-for

12 letters:
entrepreneur, restaurateur, heliogravure, photogravure, pied-a-terre, psittacosaur, savoir-faire, staurikosaur, uncalled-for, unlooked-for, unwished-for

13 letters:
questionnaire, conventioneer, laissez-faire, porte-cochere

14 letters:
concessionaire, commissionaire, surface-to-air

15 letters:
kilovolt-ampere

16 letters:
pachycephalosaur