There are 599 twelve-letter words containing A, C, G, I and T, https://www.bestwordlist.com/c/a/5/12letterwordswithacgit.htm ACAROLOGISTS ACCELERATING ACCENTUATING ACCUMULATING ADJUDICATING AEROMAGNETIC AETIOLOGICAL AFFECTIONING AGAMOGENETIC AGNOSTICISMS AGRAMMATICAL AGRICULTURAL AGRICULTURES AGRIPRODUCTS AGROSTOLOGIC ANAGLYPTICAL ANAGRAMMATIC ANASTIGMATIC ANDROGENETIC ANNUNCIATING ANTAGONISTIC ANTHOLOGICAL ANTIALLERGIC ANTICIPATING ANTICLOTTING ANTIDOGMATIC ANTIGENICITY ANTILYNCHING ANTIMAGNETIC ANTIPOACHING AORTOGRAPHIC APOGEOTROPIC APOLOGETICAL APOTHEGMATIC APPRECIATING APPRENTICING ARCHEGONIATE ARCHEOLOGIST ARCHITECTING ARTICULATING ASCERTAINING ASEPTICISING ASEPTICIZING ASTACOLOGIES ASTACOLOGIST ASTRINGENCES ASTROLOGICAL ATHEOLOGICAL ATTRACTINGLY AUSCULTATING AUTECOLOGIES BACKCHATTING BACKFITTINGS BACKLIGHTING BACKSTABBING BACKSTALLING BACKSTAMPING BACKSTARTING BACKSTOPPING BACKSTRAIGHT BACKSTROKING BACKTRACKING BACTERIOLOGY BANDICOOTING BATHYGRAPHIC BATHYPELAGIC BATTOLOGICAL BESCATTERING BIOGENETICAL BIOMAGNETICS BIRDWATCHING BLACKLISTING BLACKTOPPING BROADCASTING CABLECASTING CACHINNATING CAENOGENETIC CAFFEINATING CAINOGENETIC CALIGINOSITY CALUMNIATING CAMPHORATING CANDLELIGHTS CANTILLATING CAPACITATING CAPITALISING CAPITALIZING CAPITULATING CARBURETTING CARDIOLOGIST CARICATURING CARPENTERING CARPOLOGISTS CARTOGRAPHIC CARTOLOGICAL CARTWHEELING CASTIGATIONS CATABOLISING CATABOLIZING CATALOGISING CATALOGIZING CATALOGUISED CATALOGUISES CATALOGUISTS CATALOGUIZED CATALOGUIZES CATECHISINGS CATECHIZINGS CATEGORIALLY CATEGORISING CATEGORIZING CATERWAULING CENTIGRAMMES CENTIMORGANS CENTRALISING CENTRALIZING CENTRIFUGALS CERARGYRITES CEROGRAPHIST CHAPTALISING CHAPTALIZING CHARACTERING CHASTENINGLY CHITCHATTING CHLORIDATING CHLORINATING CINEMATISING CINEMATIZING CIRCULATINGS CIRCUMGYRATE CLADOGENETIC CLATTERINGLY CLEARCUTTING CLEISTOGAMIC CLIMATOLOGIC CLISTOGAMIES COACERVATING COAGULATIONS COASTEERINGS COCAPTAINING COGENERATION COGITATINGLY COGITATIVELY COGNOMINATED COGNOMINATES COLLEGIALITY COLLEGIATELY COLLIGATIONS COLLIQUATING COLOGARITHMS COLORCASTING COMMENTATING COMPAGINATED COMPAGINATES COMPENSATING COMPLICATING COMPURGATION CONCILIATING CONDENSATING CONFIGURATED CONFIGURATES CONFIGURATOR CONFISCATING CONGELATIONS CONGENIALITY CONGENITALLY CONGLOBATING CONGLOBATION CONGLUTINANT CONGLUTINATE CONGREGATING CONGREGATION CONGREGATIVE CONJUGATINGS CONJUGATIONS CONSECRATING CONSIGNATION CONSIGNATORY CONSOCIATING CONSTIPATING CONSTRAINING CONSUMMATING CONTAGIONIST CONTAGIOUSLY CONTIGNATION CONTRAVENING CONVERSATING COORDINATING COPARTNERING COPROPHAGIST CORRUGATIONS COTANGENTIAL COUNTERIMAGE CRANIOLOGIST CRENELLATING CRYPTOGAMIAN CRYPTOGAMIES CRYPTOGAMIST CRYSTALISING CRYSTALIZING CYANOGENETIC DACTYLIOLOGY DEACTIVATING DECAPITATING DECELERATING DECOLORATING DEGLACIATION DENUNCIATING DEPRECIATING DERACINATING DERMATOLOGIC DETOXICATING DETRACTINGLY DETRUNCATING DIABETOGENIC DIAGEOTROPIC DIAGNOSTICAL DIAGRAMMATIC DIALECTOLOGY DIJUDICATING DILACERATING DILUCIDATING DISAFFECTING DISCULPATING DISSOCIATING DITTOGRAPHIC DIVARICATING DOGMATICALLY DOOMWATCHING ECHOLOCATING EDULCORATING EFFECTUATING EGOCENTRICAL EGOISTICALLY ELASTICATING ELASTICISING ELASTICIZING ELUCUBRATING EMANCIPATING EMASCULATING ENCHANTINGLY ENCURTAINING ENTRANCINGLY EPEXEGETICAL EPIGRAMMATIC EPISCOPATING EQUIVOCATING EROTOLOGICAL ESCAPOLOGIST ESCHATOLOGIC ETHNOGRAPHIC ETHNOLOGICAL ETYMOLOGICAL EULOGISTICAL EVANGELISTIC EVISCERATING EXACERBATING EXACTINGNESS EXCOGITATING EXCOGITATION EXCOGITATIVE EXCOGITATORS EXCRUCIATING EXEGETICALLY EXTRALOGICAL EXULCERATING FACEPLANTING FACILITATING FANATICISING FANATICIZING FELICITATING FLOCCULATING FLOWCHARTING FORECASTINGS FORETEACHING GALACTOSEMIA GALACTOSEMIC GALACTOSIDES GALRAVITCHED GALRAVITCHES GAMETOPHORIC GAMETOPHYTIC GAMIFICATION GASIFICATION GASOMETRICAL GASTROCNEMII GASTRONOMICS GASTROSCOPIC GASTROTRICHS GATECRASHING GEANTICLINAL GEANTICLINES GEMEINSCHAFT GENERATRICES GENETHLIACAL GENETHLIACON GENICULATELY GENICULATING GENICULATION GEOBOTANICAL GEOCENTRICAL GEODETICALLY GEOGNOSTICAL GEOLOCATIONS GEOMETRICIAN GEOPOLITICAL GEOSTRATEGIC GEOTECHNICAL GERIATRICIAN GESTICULATED GESTICULATES GESTICULATOR GIGANTICALLY GIGANTICIDES GIGANTICNESS GIGANTOMACHY GILRAVITCHED GILRAVITCHES GLACIOLOGIST GLOSSEMATICS GLYCERINATED GLYCERINATES GONADOTROPIC GRACIOSITIES GRADUALISTIC GRAMMATICISE GRAMMATICISM GRAMMATICIZE GRANOLITHICS GRANULOCYTIC GYNECOCRATIC GYNECOMASTIA GYROMAGNETIC HAEMATOGENIC HAEMATOLOGIC HAIRCUTTINGS HANDCRAFTING HECTOGRAPHIC HEPATICOLOGY HERETICATING HISTOLOGICAL HYETOGRAPHIC HYGROCHASTIC ICHTHYOPHAGY ILLEGITIMACY ILLOGICALITY INACTIVATING INCATENATING INCINERATING INCOGITATIVE INCRASSATING INGRAVESCENT INOSCULATING INTERARCHING INTERCHANGED INTERCHANGER INTERCHANGES INTERFACINGS INTERGLACIAL INTERSPACING INTOXICATING IRRADICATING ISOANTIGENIC ISOMAGNETICS JACKLIGHTING KAINOGENETIC KICKSTARTING LATCHSTRINGS LEGITIMACIES LIMACOLOGIST LINECASTINGS LINGUISTICAL LITHOGRAPHIC LITHOLOGICAL LITURGICALLY LOGICALITIES LOGISTICALLY LOGISTICIANS LOGOMACHISTS LONGICAUDATE LYMPHANGITIC MAGISTRACIES MAGNETICALLY MAGNETICIANS MALACOLOGIST MARTYROLOGIC MATCHMAKINGS MATCHMARKING MEATPACKINGS MERCHANTINGS METAGALACTIC METALLOGENIC METATUNGSTIC METROLOGICAL MICROGAMETES MICROGRANITE MICROGRAVITY MISCATALOGED MISCATALOGUE MISCEGENATED MISCEGENATES MISCEGENATOR MISEDUCATING MONOGAMISTIC MUTAGENICITY MYCOPHAGISTS MYSTAGOGICAL MYTHOLOGICAL NEGATIVISTIC NEWSCASTINGS NIDIFICATING NIGHTCLASSES NOCTIVAGANTS NONANTIGENIC NONSTRATEGIC NOSTOLOGICAL OBTRUNCATING OCEANOLOGIST OCTOGENARIAN OCTOGENARIES OLIGOCHAETES ORGANICISTIC ORGANICITIES ORGANOLEPTIC ORGASTICALLY ORTHOGNATHIC ORTHOGRAPHIC OSTEOLOGICAL OUTACHIEVING OUTBALANCING OUTCAVILLING OUTCRAFTYING OUTLAUNCHING OUTPREACHING OUTSCREAMING OVERCASTINGS OVERCATCHING OVERCOATINGS OVERMATCHING OVERREACTING OVERTEACHING OVERWATCHING PACESETTINGS PACIFICATING PAEDOGENETIC PALINGENETIC PANTOGRAPHIC PARACHUTINGS PARADIGMATIC PARALOGISTIC PARAMAGNETIC PARATUNGSTIC PATCHWORKING PATHOGENETIC PATHOLOGICAL PATROLOGICAL PERNOCTATING PESTOLOGICAL PETROGRAPHIC PETROLOGICAL PHAGOCYTICAL PHAGOCYTISED PHAGOCYTISES PHAGOCYTISMS PHAGOCYTIZED PHAGOCYTIZES PHAGOCYTOSIS PHAGOCYTOTIC PHLEGMATICAL PHOTOGRAPHIC PHYTOGRAPHIC PHYTOLOGICAL PICTOGRAPHIC PLAGIARISTIC PLAGIOTROPIC PLASTICISING PLASTICIZING POSTORGASMIC POSTSURGICAL PRAGMATICISM PRAGMATICIST PRAGMATISTIC PRECOGNISANT PRECOGNIZANT PROGRAMMATIC PUGILISTICAL PUNCTULATING PYROMAGNETIC QUITCLAIMING RACKETEERING RACONTEURING REACTIVATING REALLOCATING RECATALOGING RECATEGORIZE RECAUTIONING RECHARTERING RECOMPACTING RECONTACTING RECUPERATING REDECORATING REDEDICATING REESCALATING REFRACTURING RETICULATING REVICTUALING ROUGHCASTING RUSTICATINGS SACRAMENTING SACRILEGISTS SALICYLATING SANCTIFYINGS SANCTIONINGS SATISFICINGS SCAMBAITINGS SCAPEGOATING SCAPEGOATISM SCATOLOGICAL SCATOLOGISTS SCATOPHAGIES SCATTERINGLY SCATTERLINGS SCHEMATISING SCHEMATIZING SCINTIGRAPHY SCRATCHINGLY SEARCHLIGHTS SECRETAGOGIC SIDETRACKING SIGNIFICANTS SIGNIFICATES SIGNIFICATOR SIMULCASTING SINGLETRACKS SPACEFLIGHTS SPHACELATING SPHRAGISTICS SPIFLICATING STAIRCASINGS STANCHELLING STANCHIONING STARFUCKINGS STENOGRAPHIC STEPDANCINGS STERCORATING STOCKTAKINGS STYLOGRAPHIC SUBSTRACTING SUFFOCATINGS SUGARCOATING SUPPLICATING SURFCASTINGS TABERNACLING TACHYGRAPHIC TAUTOLOGICAL TELEOLOGICAL TELERGICALLY TERMAGANCIES THAUMATURGIC THEURGICALLY THIGMOTACTIC THUMBTACKING TOWNSCAPINGS TRACKLAYINGS TRAFFICKINGS TRAGICALNESS TRAGICOMICAL TRANSCENDING TRANSCRIBING TRANSFECTING TRIBOLOGICAL TRICHOGYNIAL TRIFURCATING TRIGLYPHICAL TRIGRAMMATIC TRIPLICATING TROPOLOGICAL TSUNAMIGENIC TYPECASTINGS UGLIFICATION UNAPOLOGETIC UNCURTAINING UNDERCOATING UNGUICULATED UNGUICULATES VATICINATING VESICULATING VICTUALLAGES VOCIFERATING WAINSCOTINGS WAINSCOTTING WAISTCOATING WALKINGSTICK WATCHDOGGING WATCHMAKINGS WATCHSPRINGS WILDCATTINGS WITCHGRASSES ZYGODACTYLIC