3 letters:
eel

4 letters:
beal, beel, beil, biel, cele, ciel, deal, deel, diel, emil, feel, feil, fiel, giel, heal, heel, ifil, keal, keel, keil, kiel, leal, meal, mele, neal, neel, neil, niel, peal, peel, peil, piel, real, reel, riel, seal, seel, teal, teel, veal, viel, weil, zeal, zele, ziel

5 letters:
-cele, abeel, abele, adeel, adiel, alkyl, aneel, armil, avile, beale, beall, beele, bheel, biehl, bleil, briel, camil, cheal, chiel, creal, creel, creil, deahl, deale, demil, diehl, diele, emile, foell, freel, friel, gheel, greal, he'll, ideal, ifill, ineel, jeiel, jheel, keele, kheel, kiehl, kneel, kreel, kuiil, lille, meehl, menil, miele, neale, neall, neele, neile, neill, nevil, odile, oneal, oneil, ophel, padil, peale, peele, piehl, piele, riehl, riell, sahil, seale, seele, sheal, sheel, shiel, skeel, smeal, speel, spiel, steal, steel, steil, stiel, sweal, tadil, teale, teall, teele, theel, thiel, tweel, uveal, vasil, veale, viele, vp hl, we'll, we ll, wheal, wheel, ziehl

6 letters:
abdeel, abdiel, abseil, abteil, adbeel, adriel, anneal, anteal, appeal, aquiel, asbeel, atweel, awheel, azbill, b-reel, barril, brasil, camile, carril, cecile, chmiel, coutil, crisil, daneel, deosil, eleele, enrile, enseal, enseel, estill, exteel, foveal, furile, gilles, hajile, havill, ideale, infiel, jabril, jameel, kameel, kneale, lucile, maciel, madill, mandil, mcdeal, mckeel, mcneal, mcneel, mcneil, mcniel, mczeal, mishil, nardil, o'neal, o'neil, odneal, olivil, oneill, ordeal, oxheal, peniel, popeil, rameal, reheel, repeal, reseal, reveal, savill, scheel, schiel, sedile, she'll, spiele, squeal, steele, stiehl, streel, terril, theall, thiele, tineal, torril, unreal, unseal, unseel, urteil, vakeel, vantil, vermil, vineal

7 letters:
aandeel, aingeal, allheal, ashriel, averill, azareel, balneal, besaiel, brazeal, braziel, camille, cardiel, cedille, cluneal, codofil, conceal, congeal, cordele, corneal, corniel, dalziel, disleal, enwheel, ezekiel, fabrile, ferrill, gadreel, gankyil, genepil, genteel, geofile, inwheel, israfil, jahleel, jarriel, jezreel, kadmiel, kasteel, kilkeel, konseal, kushiel, lacteal, lucille, macneal, macneil, magdiel, makreel, maschil, mattiel, mcgreal, mcneill, morrill, mosgiel, nephele, o'neill, oatmeal, othniel, paralel, pasquil, poicile, ramciel, scheele, schiele, scibile, seefeel, senthil, shakeel, spaceil, surreal, tarheel, tarseal, terrile, trainel, unideal, unsteel, vanheel, verrill, vorteil, zabdiel, zadkiel, zavadil

8 letters:
adenylyl, aiguille, all-heal, ardshiel, backheel, becerril, beispiel, bergmeal, beseleel, bezaleel, big-deal, bonemeal, bonspiel, bootheel, bracteal, carnevil, caroteel, chipseal, clozaril, cogwheel, coquille, cornmeal, cusk-eel, donedeal, dropmeal, empyreal, entocele, fin keel, fishmeal, flyadeal, flywheel, forefeel, fur seal, futureal, gardasil, halophil, hananeel, hartfiel, hymeneal, hyoideal, immobile, inchmeal, intersil, jegudiel, laetrile, limbmeal, lipophil, macneill, megadeal, mendivil, merocele, monreale, nachteil, newsreel, new deal, nonideal, oil meal, onewheel, otosteal, overdeal, pernille, peroneal, philomel, pinwheel, plasteel, pospisil, pourriel, prinivil, racaille, raw deal, sand eel, sangreal, selfheal, showreel, silmaril, snapdeal, somedeal, spadille, sphacele, toxophil, tredille, usmobile, vandriel, verticel, villamil, voordeel, vorspiel, wolf-eel, zaphkiel, zoogleal

9 letters:
anglophil, anguineal, apostille, arms deal, automobil, automovil, azurophil, barachiel, big wheel, blind eel, bone-meal, bonesteel, breazeale, brindille, broadseal, cartwheel, car wheel, chrusciel, citisteel, clearasil, cochineal, cockateel, cog-wheel, congo eel, corneille, demidevil, dormobile, drop keel, ectosteal, ego ideal, endosteal, enterdeal, essentiel, fair deal, fascimile, finestill, firewheel, fish meal, freewheel, galadriel, gearwheel, good-feel, good deal, gramineal, guayaquil, hair seal, handwheel, harp seal, heat-seal, huamachil, hyperreal, interdeal, interpeal, iron heel, jerahmeel, jonquille, mesogleal, millwheel, monowheel, moray eel, motijheel, mouthfeel, myelocele, nethaneel, nonpareil, nosewheel, open-reel, paragrele, parosteal, pectineal, piecemeal, pierceall, potentiel, prontosil, salathiel, sarathiel, semisteel, shaquille, sialocele, sidewheel, singspiel, stamineal, stomodeal, subniveal, syringeal, szczygiel, tadalafil, tonewheel, troopmeal, true seal, two-wheel, uncongeal, undermeal, underseal, ungenteel, vorurteil, watermeal, wheatmeal, wheat eel, wholemeal, wire-heel, wortspiel, zerachiel

10 letters:
abbeyfeale, arthrocele, audiophile, automobile, barry seal, beau ideal, bimestriel, blood meal, bookmobile, break seal, brettspiel, chainwheel, clendaniel, colmesneil, common eel, conger-eel, conger eel, cuban heel, dahabshiil, daisywheel, eared seal, ectomobile, ed o'neill, escadrille, espadrille, fellowfeel, femorocele, festspiele, fire-wheel, four-wheel, francophil, gear wheel, goggomobil, goldenseal, great deal, great seal, halfendeal, hard steel, heterophil, hinterteil, hohentwiel, idle wheel, kakkakuyil, kasa-e-dil, kriegspiel, lemon peel, macrothele, manchineel, memorabile, mild steel, mouth-feel, neutrophil, oldsmobile, panzerkeil, periosteal, peritoneal, pneumocele, printwheel, proctodeal, real steel, roast veal, ron popeil, rosensteel, rosenstiel, sex-appeal, sex appeal, side-wheel, snowmobile, spike heel, spur wheel, talkmobile, tetraskele, thumbwheel, thyroideal, tool steel, treadwheel, velomobile, villarreal, waterwheel, wedge heel, worm wheel

11 letters:
alloy steel, alprostadil, anoperineal, arc-en-ciel, a good deal, banana peel, bestandteil, bluesmobile, breastwheel, color wheel, common seal, count-wheel, counterseal, cut of veal, daisy wheel, diyar-e-dil, drill steel, emery wheel, exponentiel, fardingdeal, ferrocarril, fifth wheel, french heel, golden seal, harbor seal, hematocoele, hippomobile, hooded seal, hudson seal, idler-wheel, indian meal, interosseal, jaime camil, key & peele, kriegsspiel, lamprey eel, mielie-meal, nic.ddn.mil, orange-peel, orange peel, paddlewheel, pericorneal, peter thiel, potato peel, rayssa leal, ryan o'neal, scape-wheel, sexlikereal, square deal, stern-wheel, therealdeal, three-wheel, tread-wheel, urethrocele, vanderweele, vinegar eel, wagon wheel, water-wheel, water wheel, yoandy leal

12 letters:
a great deal, bearded seal, bradley beal, carbon steel, chisel steel, counterwheel, damask steel, down-at-heel, earless seal, electric eel, escape wheel, ferris wheel, glockenspiel, haematocoele, jordan peele, medium steel, nayib bukele, nickel steel, oona o'neill, paddle-wheel, paddle wheel, peter steele, planet wheel, prayer wheel, reel-to-reel, richard kiel, saint-mihiel, sliding keel, soybean meal, stacked heel, tatum o'neal, thundersteel

13 letters:
achromatophil, balance-wheel, balance wheel, bicycle wheel, business deal, consanguineal, donnie steele, driving wheel, electromobile, elephant seal, fahadh faasil, iliopectineal, l'arc-en-ciel, lantern wheel, polycarbophil, preperitoneal, properitoneal, scottish reel, solomons-seal, stiletto heel, subperitoneal, susie o'neill, toothed wheel, virginia reel, wolfram steel

14 letters:
achilles' heel, breaking wheel, breast of veal, chromium steel, crabeater seal, crucible steel, damascus steel, freshwater eel, grinding wheel, maggie macneil, paraperitoneal, patrice o'neal, potter's wheel, prashanth neel, roulette wheel, shabby-genteel, spinning-wheel, spinning wheel, sprocket wheel, steering wheel, tungsten steel, vanadium steel

15 letters:
alaska fur seal, catherine wheel, extraperitoneal, fibulocalcaneal, grapefruit peel, intraperitoneal, lord privy seal, maggie mac neil, manganese steel, personal appeal, retroperitoneal, saab automobile, stainless-steel, stainless steel, transperitoneal

16 letters:
abdominoperineal, cystourethrocele, down-at-the-heel, molybdenum steel, pleuroperitoneal, shaquille o'neal, structural steel

17 letters:
daisy print wheel, fibrochondrosteal

18 letters:
guadalupe fur seal

19 letters:
candied citrus peel, contract under seal, electric automobile, you shall not steal

20 letters:
rathaus-glockenspiel

22 letters:
pinion and crown wheel

6 letters:
earful, morsel, carful, dorsal, serval, ireful, parcel, tarsal, jarful, marvel

7 letters:
martial, marshal, fearful, servile, direful, careful, tearful, partial, chervil

8 letters:
marshall, cheerful

9 letters:
impartial, colourful

10 letters:
commercial, metatarsal

11 letters:
overcareful, transversal

12 letters:
earl marshal

13 letters:
field marshal, controversial, john marshall

15 letters:
provost marshal, uncontroversial