There are 680 twelve-letter words containing A, E, F and I, https://www.bestwordlist.com/c/a/4/12letterwordswithaefi.htm
ACRIFLAVINES AERIFICATION AFFABILITIES AFFECTATIONS AFFECTIONATE
AFFECTIONING AFFIRMATIVES AFFLICTIVELY AFFLUENTIALS AFFRANCHISED
AFFRANCHISES AFFRICATIVES AFFRIGHTEDLY AFFRIGHTENED AFFRIGHTMENT
AFTERBURNING AFTERPARTIES AIRCRAFTSMEN AIRFREIGHTED AMENTIFEROUS
ANGLERFISHES ANTIFEBRILES ANTIFEMININE ANTIFEMINISM ANTIFEMINIST
AQUAFORTISES ARCHERFISHES ARFVEDSONITE ASSAFOETIDAS ASSUEFACTION
BATTLEFIELDS BEATIFICALLY BEAUTIFULLER BENEFACTIONS BENEFICIALLY
BENEFICIATED BENEFICIATES BIFLAGELLATE BIOFEEDBACKS BLUESNARFING
BREAKFASTING CAFFEINATING CALEFACIENTS CALEFACTIONS CAMPODEIFORM
CANDLEFISHES CAULIFLORIES CAULIFLOWERS CEFTRIAXONES CENTRIFUGALS
CERTIFICATED CERTIFICATES CHAETIFEROUS CHAUFFEURING CHAUFFEUSING
CHIEFTAINESS CLAMJAMFRIES CLASSIFIABLE CLIFFHANGERS COMPACTIFIED
COMPACTIFIES CONFERENTIAL CONFESSIONAL CONFIDENTIAL CONFIGURATED
CONFIGURATES CONFIRMATIVE CRAFTINESSES CURVIFOLIATE DAFFODILLIES
DAMSELFISHES DANDRUFFIEST DEACIDIFYING DECAFFEINATE DECALCIFIERS
DECALCIFYING DECLASSIFIED DECLASSIFIES DECRASSIFIED DECRASSIFIES
DEFAECATIONS DEFALCATIONS DEFAMATORILY DEFENSATIVES DEFEUDALISED
DEFEUDALISES DEFEUDALIZED DEFEUDALIZES DEFIBRILLATE DEFIBRINATED
DEFIBRINATES DEFILIATIONS DEFINABILITY DEFINITIONAL DEFLAGRATING
DEFLAGRATION DEFLATIONARY DEFLATIONIST DEFLECTIONAL DEFLORATIONS
DEFOLIATIONS DEFORCIATION DEFORMALISED DEFORMALISES DEFORMALIZED
DEFORMALIZES DEFORMATIONS DEFRAUDATION DEIFICATIONS DESANCTIFIED
DESANCTIFIES DIBENZOFURAN DIFFERENTIAE DIFFERENTIAL DIFFRANGIBLE
DISAFFECTING DISAFFECTION DISAFFILIATE DISAFFORESTS DISFAVOURERS
DISFEATURING DISFRANCHISE DISINFECTANT DISINFESTANT DISQUALIFIED
DISQUALIFIER DISQUALIFIES DISREGARDFUL DISSATISFIED DISSATISFIES
DOLLARFISHES DRAFTINESSES DRAGONFISHES DWARFISHNESS EDIFICATIONS
EFFECTUALITY EFFECTUATING EFFECTUATION EFFEMINACIES EFFEMINATELY
EFFEMINATING EFFICACITIES EFFIGURATION EFFLEURAGING EISTEDDFODAU
EMULSIFIABLE ENFRANCHISED ENFRANCHISER ENFRANCHISES ENGRAFTATION
EXFILTRATING EXFILTRATION EXFOLIATIONS EXSUFFLATING EXSUFFLATION
EXSUFFLICATE FABULOSITIES FACEPLANTING FACILENESSES FACILITATIVE
FACSIMILEING FACTIONALISE FACTIONALIZE FACTIONARIES FACTIOUSNESS
FACTUALITIES FAINEANTISES FAINTHEARTED FAINTISHNESS FAIRNITICKLE
FAIRNITICLES FAIRNYTICKLE FAIRNYTICLES FAIRYFLOSSES FAITHFULNESS
FALDISTORIES FALLIBLENESS FAMILIARISED FAMILIARISER FAMILIARISES
FAMILIARIZED FAMILIARIZER FAMILIARIZES FAMILIARNESS FANCIFULNESS
FANTASTICATE FANTASTICOES FARCICALNESS FARNARKELING FARSIGHTEDLY
FARTHINGALES FARTHINGLESS FASCICULATED FASCINATEDLY FASCIOLIASES
FASHIONABLES FASHIOUSNESS FATHERLINESS FAULTFINDERS FAULTINESSES
FEASIBLENESS FEATHERBRAIN FEATHERINESS FEATHERLIGHT FEATLINESSES
FEBRIFACIENT FECUNDATIONS FEDERALISING FEDERALISTIC FEDERALIZING
FEDERATIVELY FELDSPATHOID FELICITATING FELICITATION FELICITATORS
FELSPATHOIDS FEMINALITIES FEMINISATION FEMINIZATION FENESTRATING
FENESTRATION FENFLURAMINE FERMENTATION FERMENTATIVE FERRICYANIDE
FERRIMAGNETS FERROCYANIDE FERTIGATIONS FERTILISABLE FERTILIZABLE
FESTINATIONS FESTIVALGOER FIANCHETTOED FIANCHETTOES FIBERGLASSED
FIBERGLASSES FIBERISATION FIBERIZATION FIBREGLASSED FIBREGLASSES
FICTIONALISE FICTIONALIZE FIGURATIVELY FILIALNESSES FILLAGREEING
FINANCIERING FINASTERIDES FINEABLENESS FINGERBOARDS FINGERGUARDS
FINGERPLATES FINGERSTALLS FINICALITIES FIRECRACKERS FIRESCAPINGS
FISSICOSTATE FISSIONABLES FISSIPALMATE FLABBINESSES FLABELLATION
FLABELLIFORM FLACCIDITIES FLAGELLATING FLAGELLATION FLAGELLIFORM
FLAGGINESSES FLAMMIFEROUS FLANNELLIEST FLASHINESSES FLATTERINGLY
FLATULENCIES FLAUGHTERING FLAVIVIRUSES FLAVOPROTEIN FLEXITARIANS
FLEXOGRAPHIC FLICKERTAILS FLIMFLAMMERS FLIMFLAMMERY FLIPPANTNESS
FLUIDEXTRACT FLUORAPATITE FLUPHENAZINE FLUVIOMARINE FLUVOXAMINES
FOLLICULATED FOMENTATIONS FONTINALISES FOOLHARDIEST FOOLHARDISES
FOOLHARDIZES FOOTWEARIEST FORAMINIFERA FORAMINIFERS FORBEARINGLY
FORBIDDANCES FORECARRIAGE FORECASTINGS FOREMANSHIPS FORENSICALLY
FOREORDAINED FOREPLANNING FOREREACHING FOREREADINGS FORESLACKING
FORESPEAKING FORESTALLING FORESTATIONS FORESTAYSAIL FORESWEARING
FORETEACHING FORETRIANGLE FOREWARNINGS FORGATHERING FORGEABILITY
FORMALISABLE FORMALIZABLE FORMULARISED FORMULARISER FORMULARISES
FORMULARIZED FORMULARIZER FORMULARIZES FORNICATRESS FORTEPIANIST
FORWANDERING FOSSILISABLE FOSSILIZABLE FOTHERGILLAS FOUNDATIONER
FOUNTAINHEAD FOUNTAINLESS FRACTALITIES FRACTIONATED FRACTIONATES
FRACTIONISED FRACTIONISES FRACTIONIZED FRACTIONIZES FRACTIONLETS
FRAGMENTISED FRAGMENTISES FRAGMENTIZED FRAGMENTIZES FRANCOPHILES
FRANKINCENSE FRANKLINITES FRATCHETIEST FRATERNALISM FRATERNISERS
FRATERNISING FRATERNITIES FRATERNIZERS FRATERNIZING FREAKINESSES
FREAKISHNESS FREELOADINGS FREESTANDING FRENETICALLY FRESHMANSHIP
FRIABILITIES FRICASSEEING FRITILLARIES FRONTALITIES FRONTIERSMAN
FRUMENTATION FUNCTIONATED FUNCTIONATES FURAZOLIDONE GEMEINSCHAFT
GLANDIFEROUS GODFATHERING GONFALONIERS GRASSFINCHES GUITARFISHES
HALFWITTEDLY HALLEFLINTAS HAMFATTERING HANDICRAFTER HANDKERCHIEF
HEXAFLUORIDE IDENTIFIABLE IDENTIFIABLY IMPERFORABLE IMPERFORATED
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 IRREFORMABLE IRREFORMABLY IRREFRAGABLE
IRREFRAGABLY LABEFACTIONS LATICIFEROUS LEAPFROGGING LIFEGUARDING
LIFEMANSHIPS LIQUEFACIENT LIQUEFACTION LIQUEFACTIVE LIQUIFACTIVE
MADEFACTIONS MAGNIFICENCE MALEFACTIONS MALEFICENCES MANIFESTABLE
MANIFESTANTS MANIFESTIBLE MANIFESTNESS MANIFESTOING MANIFOLDNESS
MEANINGFULLY METAFICTIONS METRIFONATES MICROFINANCE MIDAFTERNOON
MISCHANCEFUL MISFEASANCES MISFEATURING MODIFICATIVE MONOFILAMENT
MULTIFACETED MULTIFEATURE MULTIFLASHES MULTIFOLIATE MUTESSARIFAT
MYOFILAMENTS NEUROFIBROMA NONFACULTIES NONFATTENING OAFISHNESSES
OFFICIALESES OFFICIALTIES OUTFANGTHIEF OVERCLASSIFY OVERFAMILIAR
OVERFATIGUED OVERFATIGUES OVERFAVORING OVERINFLATED OVERINFLATES
OVERSTAFFING PADDLEFISHES PAPULIFEROUS PARAFFINIEST PARFOCALISED
PARFOCALISES PARFOCALIZED PARFOCALIZES PARROTFISHES PARVIFOLIATE
PERFECTATION PERFOLIATION PERFORATIONS PERFORMATIVE PETALIFEROUS
PETRIFACTION PETRIFACTIVE PLACENTIFORM PONTIFICATED PONTIFICATES
PREACHIFYING PREAMPLIFIER PREFABRICATE PREFECTORIAL PREFERENTIAL
PREFIGURATED PREFIGURATES PREFINANCING PREFLORATION PREFOLIATION
PREFORMATION PREFORMATIVE PREQUALIFIED PREQUALIFIES PRIESTCRAFTS
PROFESSIONAL PROFESSORIAL PROFESSORIAT PROFLIGACIES PROFLIGATELY
PROLIFERATED PROLIFERATES PROOFREADING PUFTALOONIES PURIFICATIVE
PUTREFACIENT PUTREFACTION PUTREFACTIVE QUANTIFIABLE QUARTERFINAL
RABBITFISHES RANGEFINDERS RANGEFINDING RAREFACTIONS RAREFICATION
RECLASSIFIED RECLASSIFIES REFASHIONING REFECTORIANS REFINANCINGS
REFLATIONARY REFLECTIONAL REFOCILLATED REFOCILLATES REFORMATIONS
REFORMATTING REFOUNDATION REFRACTARIES REFRACTIVELY REFRACTIVITY
REFRACTORIES REFRACTORILY REFRACTURING REFRAINMENTS REFRIGERANTS
REFRIGERATED REFRIGERATES REFRIGERATOR REFUTABILITY REIFICATIONS
REINFLATIONS REQUALIFYING RIBOFLAVINES RIFACIMENTOS RUBEFACIENTS
RUBEFACTIONS SACCHARIFIED SACCHARIFIES SAFECRACKING SAFEGUARDING
SAFEKEEPINGS SALUTIFEROUS SANCTIFIABLE SANCTIFIEDLY SANGUIFEROUS
SAPONIFIABLE SATINFLOWERS SCIENTIFICAL SEMIFINALIST SEMIOFFICIAL
SHAPESHIFTER SHEATHFISHES SIGNIFICANCE SIGNIFICATES SIMPLIFIABLE
SINFONIETTAS SOLIDIFIABLE SOMNIFACIENT SORBEFACIENT SPACEFARINGS
SPACEFLIGHTS SPEARFISHING SPECIFICALLY SPECIFICATED SPECIFICATES
SPIFFLICATED SPIFFLICATES STANNIFEROUS STEAMFITTERS STEPFAMILIES
STUPEFACIENT STUPEFACTION STUPEFACTIVE SUBFACULTIES SUBFEUDATION
SUBINFEUDATE SUFFUMIGATED SUFFUMIGATES SULFADIAZINE SULFADOXINES
SULFONAMIDES SUPERFICIALS TABEFACTIONS TEPEFACTIONS TERRAFORMING
TERRIFICALLY TESTIFICATES TESTIFICATOR THEREINAFTER THIOSULFATES
TIBIOFIBULAE TITANIFEROUS TORREFACTION TRAFFICKIEST TRANSFECTING
TRANSFECTION TRANSFERRING TRANSFERRINS TRANSFIGURED TRANSFIGURES
TRANSFUSIBLE TRIFOLIOLATE TRYPAFLAVINE TUFTAFFETIES TUMEFACTIONS
ULTRAFILTERS ULTRALEFTISM ULTRALEFTIST ULTRAREFINED UNAFFILIATED
UNBENEFICIAL UNCLASSIFIED UNCONFINABLE UNDEFOLIATED UNFADINGNESS
UNFAIRNESSES UNFATHERLIER UNFEUDALISED UNFEUDALISES UNFEUDALIZED
UNFEUDALIZES UNFILTERABLE UNFLATTERING UNFORGIVABLE UNFORMALISED
UNFORMALIZED UNFORMIDABLE UNFRANCHISED UNIFOLIOLATE UNMODIFIABLE
UNPROFITABLE UNQUANTIFIED UNSANCTIFIED UNSANCTIFIES UNSTRATIFIED
UNVERIFIABLE UNVERIFIABLY VERIFICATION VERIFICATIVE VERIFICATORY
VERSIFICATOR VITRIFACTURE VOCIFERANCES VOCIFERATING VOCIFERATION
VOCIFERATORS WATERFINDERS WATERFOWLING WEARIFULNESS WINEGLASSFUL