There are 607 twelve-letter words containing A, E, F and N, https://www.bestwordlist.com/c/a/4/12letterwordswithaefn.htm
ACRIFLAVINES ADVENTUREFUL AERIFICATION AFFECTATIONS AFFECTEDNESS
AFFECTIONATE AFFECTIONING AFFLUENTIALS AFFLUENTNESS AFFORCEMENTS
AFFRANCHISED AFFRANCHISES AFFRIGHTENED AFFRIGHTMENT AFTERBURNERS
AFTERBURNING AIRCRAFTSMEN AMENTIFEROUS ANGLERFISHES ANTIFEBRILES
ANTIFEMININE ANTIFEMINISM ANTIFEMINIST ARFVEDSONITE ARTFULNESSES
ASSUEFACTION BATTLEFRONTS BENEFACTIONS BENEFACTRESS BENEFICIALLY
BENEFICIATED BENEFICIATES BLAMEFULNESS BLUESNARFING BOASTFULNESS
BRASSFOUNDER BREAKFASTING CAFFEINATING CALEFACIENTS CALEFACTIONS
CANDLEFISHES CANDYFLOSSES CAREFREENESS CEFTRIAXONES CENTRIFUGALS
CHAUFFEURING CHAUFFEUSING CHIEFTAINESS CLIFFHANGERS CODEFENDANTS
CONFABULATED CONFABULATES CONFEDERATED CONFEDERATES CONFERENTIAL
CONFESSIONAL CONFIDENTIAL CONFIGURATED CONFIGURATES CONFIRMATIVE
CONFLAGRATED CONFLAGRATES CONFORMANCES CONFOUNDABLE CONFRATERNAL
COUNTERSHAFT CRAFTINESSES CRAFTSPERSON DANDRUFFIEST DEACIDIFYING
DECAFFEINATE DECALCIFYING DEFAECATIONS DEFALCATIONS DEFENESTRATE
DEFENSATIVES DEFIBRINATED DEFIBRINATES DEFILIATIONS DEFINABILITY
DEFINITIONAL DEFLAGRATING DEFLAGRATION DEFLATIONARY DEFLATIONIST
DEFLECTIONAL DEFLOCCULANT DEFLORATIONS DEFOLIATIONS DEFORCIATION
DEFORMATIONS DEFRAGMENTED DEFRAGMENTER DEFRAUDATION DEFRAUDMENTS
DEIFICATIONS DESANCTIFIED DESANCTIFIES DIBENZOFURAN DIFFERENTIAE
DIFFERENTIAL DIFFRANGIBLE DISAFFECTING DISAFFECTION DISFEATURING
DISFRANCHISE DISINFECTANT DISINFESTANT DRAFTINESSES DRAFTSPERSON
DRAGONFISHES DREADFULNESS DREAMFULNESS DWARFISHNESS EDIFICATIONS
EFFECTUATING EFFECTUATION EFFEMINACIES EFFEMINATELY EFFEMINATING
EFFIGURATION EFFLEURAGING ENFRAMEMENTS ENFRANCHISED ENFRANCHISER
ENFRANCHISES ENGRAFTATION ENGRAFTMENTS ENTOMOFAUNAE ENTOMOFAUNAS
EXFILTRATING EXFILTRATION EXFOLIATIONS EXSUFFLATING EXSUFFLATION
FABULOUSNESS FACELESSNESS FACEPLANTING FACILENESSES FACSIMILEING
FACTIONALISE FACTIONALIZE FACTIONARIES FACTIOUSNESS FAINEANTISES
FAINTHEARTED FAINTISHNESS FAIRNITICKLE FAIRNITICLES FAIRNYTICKLE
FAIRNYTICLES FAITHFULNESS FALLENNESSES FALLIBLENESS FALLOWNESSES
FAMILIARNESS FAMOUSNESSES FANCIFULNESS FANFARONADED FANFARONADES
FANTASTICATE FANTASTICOES FARCICALNESS FARNARKELING FARTHINGALES
FARTHINGLESS FASCINATEDLY FASHIONABLES FASHIOUSNESS FATHERLINESS
FAULTFINDERS FAULTINESSES FAVOUREDNESS FEARLESSNESS FEARSOMENESS
FEASIBLENESS FEATHERBRAIN FEATHERINESS FEATLINESSES FEBRIFACIENT
FECUNDATIONS FEDERALISING FEDERALIZING FELICITATING FELICITATION
FEMALENESSES FEMINALITIES FEMINISATION FEMINIZATION FENESTRATING
FENESTRATION FENFLURAMINE FERMENTATION FERMENTATIVE FERRICYANIDE
FERRIMAGNETS FERROCYANIDE FERROMAGNETS FERTIGATIONS FESTINATIONS
FIANCHETTOED FIANCHETTOES FIBERISATION FIBERIZATION FICTIONALISE
FICTIONALIZE FILIALNESSES FILLAGREEING FINANCIERING FINASTERIDES
FINEABLENESS FINGERBOARDS FINGERGUARDS FINGERPLATES FINGERSTALLS
FINICALITIES FIRESCAPINGS FISSIONABLES FLABBINESSES FLABELLATION
FLAGELLATING FLAGELLATION FLAGGINESSES FLAGRANTNESS FLAMBOYANCES
FLAMBOYANTES FLANNELBOARD FLANNELETTES FLANNELGRAPH FLANNELLIEST
FLASHINESSES FLATTERINGLY FLATULENCIES FLAUGHTERING FLAVOPROTEIN
FLAWLESSNESS FLEXITARIANS FLIPPANTNESS FLUCONAZOLES FLUPHENAZINE
FLUVIOMARINE FLUVOXAMINES FOMENTATIONS FONTINALISES FOOTBALLENES
FOOTPLATEMAN FOOTPLATEMEN FORAMINIFERA FORAMINIFERS FORBEARANCES
FORBEARINGLY FORBIDDANCES FORECASTINGS FOREHANDEDLY FOREKNOWABLE
FOREMANSHIPS FORENSICALLY FOREORDAINED FOREPAYMENTS FOREPLANNING
FOREREACHING FOREREADINGS FORESLACKING FORESPEAKING FORESTALLING
FORESTALMENT FORESTATIONS FORESWEARING FORETEACHING FORETRIANGLE
FOREWARNINGS FORGATHERING FORMALNESSES FORNICATRESS FORSAKENNESS
FORTEPIANIST FORWANDERING FOUNDATIONER FOUNTAINHEAD FOUNTAINLESS
FRACTIONATED FRACTIONATES FRACTIONISED FRACTIONISES FRACTIONIZED
FRACTIONIZES FRACTIONLETS FRAGMENTALLY FRAGMENTATED FRAGMENTATES
FRAGMENTISED FRAGMENTISES FRAGMENTIZED FRAGMENTIZES FRAGRANTNESS
FRANCOPHILES FRANCOPHOBES FRANCOPHONES FRANKFURTERS FRANKINCENSE
FRANKLINITES FRANKPLEDGES FRATERNALISM FRATERNISERS FRATERNISING
FRATERNITIES FRATERNIZERS FRATERNIZING FRAUDULENCES FRAUDULENTLY
FREAKINESSES FREAKISHNESS FREEHANDEDLY FREELOADINGS FREESTANDING
FRENETICALLY FREQUENTABLE FRESHMANSHIP FRICASSEEING FRONTALITIES
FRONTIERSMAN FRUGALNESSES FRUMENTATION FUNAMBULATED FUNAMBULATES
FUNCTIONATED FUNCTIONATES FUNDAMENTALS FURAZOLIDONE FURTHERANCES
GEMEINSCHAFT GLANDIFEROUS GODFATHERING GONFALONIERS GRACEFULNESS
GRANDFATHERS GRASSFINCHES GRATEFULNESS HALFENDEALES HALLEFLINTAS
HAMFATTERING HANDICRAFTER HANDKERCHIEF HASENPFEFFER HENCEFORWARD
HERPETOFAUNA IDENTIFIABLE IDENTIFIABLY INDEFEASIBLE INDEFEASIBLY
INDEFINABLES INEFFABILITY INEFFACEABLE INEFFACEABLY INEFFICACIES
INEFFICACITY INFAMOUSNESS INFANGTHIEFS INFANTICIDES INFANTILISED
INFANTILISES INFANTILIZED INFANTILIZES INFATUATEDLY INFESTATIONS
INFEUDATIONS INFILTRATIVE INFLAMMABLES INFLATEDNESS INFLECTIONAL
INFLUENTIALS INFOMERCIALS INFORMATISED INFORMATISES INFORMATIZED
INFORMATIZES INFORMIDABLE INFOTAINMENT INFRACLASSES INGRAFTMENTS
INSUFFERABLE INSUFFERABLY INTERFACINGS INTERFACULTY INTERFEMORAL
INTERFLUVIAL INTERFOLIATE INTERFRONTAL INTERGRAFTED INTERTRAFFIC
JALOALLOFANE LABEFACTIONS LAWFULNESSES LEAFLESSNESS LEAPFROGGING
LIFEGUARDING LIFEMANSHIPS LIQUEFACIENT LIQUEFACTION LOATHFULNESS
MADEFACTIONS MAGNIFICENCE MALEFACTIONS MALEFICENCES MALFEASANCES
MANFULNESSES MANIFESTABLE MANIFESTANTS MANIFESTIBLE MANIFESTNESS
MANIFESTOING MANIFOLDNESS MANUFACTURED MANUFACTURER MANUFACTURES
MEANINGFULLY METAFICTIONS METRIFONATES MICROFINANCE MIDAFTERNOON
MISCHANCEFUL MISFEASANCES MISFEATURING MONOFILAMENT MYOFILAMENTS
NEEDLECRAFTS NEUROFIBROMA NEWFANGLEDLY NONFACULTIES NONFATTENING
NONFEASANCES NONFEDERATED NONFLAMMABLE OAFISHNESSES OUTFANGTHIEF
OVERFAVORING OVERINFLATED OVERINFLATES OVERSTAFFING PARAFFINIEST
PEACEFULNESS PERFECTATION PERFOLIATION PERFORATIONS PERFORMANCES
PETRIFACTION PLACENTIFORM PONTIFICATED PONTIFICATES PREACHIFYING
PREFERENTIAL PREFINANCING PREFLORATION PREFOLIATION PREFORMATION
PROFESSIONAL PROOFREADING PUFTALOONIES PUTREFACIENT PUTREFACTION
QUANTIFIABLE QUARTERFINAL RANGEFINDERS RANGEFINDING RAREFACTIONS
RAREFICATION REFASHIONING REFECTORIANS REFINANCINGS REFLATIONARY
REFLECTANCES REFLECTIONAL REFORMATIONS REFORMATTING REFOUNDATION
REFRACTURING REFRAINMENTS REFRIGERANTS REIFICATIONS REINFLATIONS
REQUALIFYING RETRANSFORMS RETRANSFUSED RETRANSFUSES RIBOFLAVINES
RIFACIMENTOS RUBEFACIENTS RUBEFACTIONS SAFECRACKING SAFEGUARDING
SAFEKEEPINGS SANCTIFIABLE SANCTIFIEDLY SANGUIFEROUS SAPONIFIABLE
SATINFLOWERS SCIENTIFICAL SCREENCRAFTS SELFSAMENESS SEMIFINALIST
SHAMEFULNESS SIGNIFICANCE SIGNIFICATES SINFONIETTAS SOMNIFACIENT
SORBEFACIENT SPACEFARINGS SPEARFISHING STANNIFEROUS STEDFASTNESS
STUPEFACIENT STUPEFACTION SUBFEUDATION SUBFRAGMENTS SUBINFEUDATE
SULFADIAZINE SULFADOXINES SULFONAMIDES SULFONYLUREA SULFORAPHANE
SUPERFRONTAL TABEFACTIONS TASTEFULNESS TEASPOONFULS TEASPOONSFUL
TEPEFACTIONS TERRAFORMING THANKFULLEST THANKFULNESS THEREINAFTER
THUNDERFLASH TITANIFEROUS TORREFACTION TRANSFECTING TRANSFECTION
TRANSFERABLE TRANSFERASES TRANSFERENCE TRANSFERRALS TRANSFERRERS
TRANSFERRING TRANSFERRINS TRANSFIGURED TRANSFIGURES TRANSFORMERS
TRANSFUSABLE TRANSFUSIBLE TRYPAFLAVINE TUMEFACTIONS ULTRAREFINED
UNAFFECTEDLY UNAFFILIATED UNAFFORDABLE UNBENEFICIAL UNCLASSIFIED
UNCONFINABLE UNDEFEATABLE UNDEFOLIATED UNDERSTAFFED UNDERSURFACE
UNFADINGNESS UNFAIRNESSES UNFATHERLIER UNFATHOMABLE UNFAVOURABLE
UNFEUDALISED UNFEUDALISES UNFEUDALIZED UNFEUDALIZES UNFILTERABLE
UNFLATTERING UNFOREWARNED UNFORGIVABLE UNFORMALISED UNFORMALIZED
UNFORMIDABLE UNFORMULATED UNFORTUNATES UNFRANCHISED UNGRACEFULLY
UNGRATEFULLY UNIFOLIOLATE UNLAWFULNESS UNMODIFIABLE UNPEACEFULLY
UNPERFORATED UNPROFITABLE UNQUANTIFIED UNREFORMABLE UNSAFENESSES
UNSANCTIFIED UNSANCTIFIES UNSTRATIFIED UNSUFFERABLE UNVERIFIABLE
UNVERIFIABLY VERIFICATION VOCIFERANCES VOCIFERATING VOCIFERATION
WASTEFULNESS WATCHFULNESS WATERFINDERS WATERFOWLING WEARIFULNESS
WINEGLASSFUL WRATHFULNESS