4 letters:
ayer, byer, dire, dyar, dyer, eyer, hier, hire, hyer, iyer, kyer, liar, mier, mire, myer, pyre, ryer, sire, tire, tyer, viar, wire, wyer

5 letters:
beier, briar, brier, bryer, buyer, choir, criar, crier, cryer, diyer, drier, dryer, dwyer, feier, flier, flyer, friar, frier, fryar, fryer, geier, grier, guier, guyer, heier, hier-, klier, krier, leier, maiar, meier, meyer, neier, plier, plyer, prier, prior, pryer, pryor, seier, shier, shyer, skyer, slier, slyer, smyer, spier, stier, styer, swier, trier, twire, twyer, wrier, wryer

6 letters:
attire, bleier, breier, briare, capire, defier, denyer, desire, dewier, dreier, ebuyer, edayar, enfire, entire, etrier, higher, ipfire, kleier, ls3/5a, mctier, mediar, nigher, odwyer, refire, relier, retire, rewire, satire, schier, scryer, sigher, speier, sprier, spryer, squier, steier, uighur, umpire, untier, unwire, variar, verier, why're, wigher

7 letters:
acquire, applier, appuyer, avodire, bonfire, condire, confiar, decrier, deifier, edifier, enfriar, ennuyer, enquire, essuyer, figuier, foxfire, fratire, gestire, gipsire, gunfire, hotwire, jetfire, madrier, mcbryar, mcguyer, misfire, partyer, pinfire, pochoir, ps-05/a, replier, replyer, require, scheier, schmier, schnier, schrier, schryer, schwier, spedire, sucrier, unifier

8 letters:
advertir, ayrshire, basifier, bitflyer, campfire, codifier, complier, conspire, crachoir, descrier, destrier, disfriar, dubilier, gasifier, hardwire, harmeyer, impedire, modifier, monifier, notifier, nyanpire, occupier, openfire, ossifier, pacifier, pimplier, portfire, purifier, quagmire, ratifier, sarplier, schleier, schneier, schreier, shahriar, spitfire, supplier, surefire, tawdrier, typifier, unattire, unretire, verifier, vivifier, whitmyer, wildfire

9 letters:
acetifier, acidifier, amplifier, antechoir, appsflyer, blowdryer, bullbrier, ceasefire, certifier, clarifier, crucifier, cualquier, densifier, didemeyer, disattire, dog-brier, doubtfire, eggemeyer, falsifier, fortifier, glorifier, gratifier, hairdrier, hairdryer, highflier, highflyer, homebuyer, horrifier, justifier, kiteflier, liquefier, longmeyer, magnifier, mattifier, mollifier, mortifier, mystifier, nitrifier, norsefire, nullifier, opacifier, qualifier, rectifier, satisfier, scarifier, scorifier, signifier, souscrire, specifier, starflyer, sure-fire, tackifier, terrifier, terrifyer, testifier, transpire, underlier, versifier, vivandire, wedemeyer, yzaguirre

10 letters:
arthrodire, beautifier, blackfriar, blow-dryer, boutonnire, calendrier, calorifier, cease-fire, classifier, coconspire, contredire, detoxifier, emulsifier, frohnmayer, fructifier, greenbriar, greenbrier, high-flier, high-flyer, horsebrier, humidifier, identifier, kinzlmaier, markiplier, multiplier, ostermeyer, prettifier, quantifier, sanctifier, sanguifier, saponifier, shanghaier, simplifier, solidifier, spare-tire, spin-drier, spin-dryer, stultifier, sweetbriar, town-crier

11 letters:
cammermeyer, decalcifier, demulsifier, denitrifier, diversifier, electrifier, exemplifier, horse-brier, indemnifier, infastidire, intensifier, personifier, premodifier, speechifier, trasgredire

12 letters:
alexisonfire, complexifier, disqualifier, postmodifier, preamplifier, tumble-dryer, washer-dryer

13 letters:
staffordshire

14 letters:
frequent-flier, owner-occupier, selective-fire, self-justifier

15 letters:
photomultiplier

16 letters:
thermomultiplier

5 letters:
hirer