There are 655 twelve-letter words containing A, M, 2S and T, https://www.bestwordlist.com/c/a/5/12letterwordswithamsst.htm ABOLISHMENTS ABSENTEEISMS ABSTEMIOUSLY ACCLIMATISES ACCOMPANISTS ACHROMATISES ACHROMATISMS ADOPTIANISMS ADOPTIONISMS ADVENTURISMS AEROTROPISMS AESTHETICISM AGNOSTICISMS AGRITOURISMS AGROTOURISMS AHISTORICISM ALLOTROPISMS ALMIGHTINESS ALTALTISSIMO AMATEURSHIPS AMAZONSTONES AMBITIONLESS AMETABOLISMS AMISSIBILITY AMPHISTOMOUS AMPHISTYLARS ANASTOMOSING ANGIOSTOMOUS ANISOTROPISM ANTIELITISMS ANTIFASCISMS ANTIMACASSAR ANTIMISSILES ANTIREALISMS ANTONOMASIAS APOLITICISMS APOSTOLICISM APOTROPAISMS APPEASEMENTS ARTEMISININS ASCOMYCETOUS ASPHETERISMS ASSEMBLAGIST ASSIMILATING ASSIMILATION ASSIMILATIVE ASSIMILATORS ASSIMILATORY ASSUAGEMENTS ASSUMABILITY ASSUMPTIVELY ASTIGMATISMS ASTONISHMENT ASTOUNDMENTS ASTROCOMPASS ASTROCYTOMAS ASTROMETRIES ASTRONOMISED ASTRONOMISES ASTRONOMIZES ASTROTOURISM ATHLETICISMS ATMOSPHERICS ATOMISATIONS ATTORNEYISMS AUTOEROTISMS AUTOSAMPLERS AVITAMINOSES AVITAMINOSIS BARGEMASTERS BARNSTORMERS BASEMENTLESS BATHMITSVAHS BATSMANSHIPS BIMETALLISMS BIMETALLISTS BLOODSTREAMS BRAGGARTISMS BREASTSUMMER BULLMASTIFFS BURGOMASTERS CALLISTEMONS CASHIERMENTS CATHETERISMS CATHOLICISMS CAUSATIONISM CHARISMATICS CHASTENMENTS CHASTISEMENT CHEMONASTIES CHEMOTAXISES CHOIRMASTERS CHORUSMASTER CHRISMATIONS CHROMOPLASTS CLICKSTREAMS CLISTOGAMIES COMMISERATES COMMISSARIAT COMMUNALISTS COMPARATISTS COMPENSATORS CONSERVATISM CONSUMMATORS CORPORATISMS CORYBANTISMS COSMETICIANS COSMOLATRIES COSMONAUTICS COSMOPLASTIC CRASSAMENTUM CREATIANISMS CREATIONISMS CRIMINALISTS CROSSMATCHED CROSSMATCHES CUSTOMISABLE DEDRAMATISES DELASSEMENTS DEMAGNETISES DEMIBASTIONS DEMOCRATISES DEMOCRATISTS DEMONSTRATES DEMUTUALISES DERMATITISES DESAGREMENTS DESPUMATIONS DEUTSCHMARKS DIASTROPHISM DIATONICISMS DIDACTICISMS DIDACTYLISMS DIPLOMATESES DIPLOMATISES DIPLOMATISTS DISABLEMENTS DISACCUSTOMS DISAMENITIES DISARMAMENTS DISBANDMENTS DISCARDMENTS DISMANTLINGS DISMASTMENTS DISMUTATIONS DISSEMINATED DISSEMINATES DISSEMINATOR DISSIMILATED DISSIMILATES DISSIMULATED DISSIMULATES DISSIMULATOR DOMESTICATES DRAMATICISMS DRILLMASTERS DYNASTICISMS DYSRHYTHMIAS EMASCULATORS EMBLEMATISES EMBLEMATISTS EMPASSIONATE EMULATRESSES ENSLAVEMENTS ENSNAREMENTS ERGASTOPLASM ESCHEATMENTS ESSENTIALISM ESTRAMAZONES EUDAEMONISTS EUDAIMONISTS EVANISHMENTS EXTERNALISMS FACSIMILISTS FANTASTICISM FATHOMLESSLY FAVOURITISMS FISSIPALMATE FORETOPMASTS FRAGMENTISES FUNAMBULISTS GALIMATIASES GAMMERSTANGS GAMOTROPISMS GANGSTERDOMS GANGSTERISMS GARNISHMENTS GASTRONOMERS GASTRONOMICS GASTRONOMIES GASTRONOMIST GASTROTOMIES GLOSSEMATICS GLUTAMINASES GNATHOSTOMES GONIMOBLASTS GOSSAMERIEST GRANDMASTERS GUESSTIMATED GUESSTIMATES GUTTURALISMS GYNAECOMASTS HAEMATEMESES HAEMATEMESIS HAEMATOLYSES HAEMATOLYSIS HAEMOSTASIAS HAEMOSTATICS HALOPHYTISMS HAMMERSTONES HARMONICISTS HARVESTTIMES HEADMISTRESS HEMATOBLASTS HEXAMETRISES HEXAMETRISTS HIPPEASTRUMS HIPPODAMISTS HISTAMINASES HOMESTEADERS HOMOBLASTIES HOMOEOSTASES HOMOEOSTASIS HOMOPLASTIES HOUSEMASTERS HUNTSMANSHIP HYLOPATHISMS IMITABLENESS IMMANENTISMS IMMANENTISTS IMMATURENESS IMMEDIATISMS IMMORTALISES IMPASSIONATE IMPASTATIONS IMPERIALISTS IMPERSONATES IMPOSTUMATES IMPROVISATES INFANTILISMS INFORMATISES INSECTARIUMS INSEMINATORS INSNAREMENTS INSTALLMENTS INSTATEMENTS INSTREAMINGS INTIMATENESS ISOLATIONISM ISOMAGNETICS ISOMETROPIAS ITEMISATIONS JUSTICIALISM LITERARYISMS LOGOMACHISTS LYMPHOBLASTS MACKINTOSHES MACROCYTOSES MACROCYTOSIS MADRIGALISTS MAGISTERIUMS MAGISTRACIES MAGNATESHIPS MAGNESSTONES MAIDSERVANTS MAINTOPMASTS MAINTOPSAILS MAISONNETTES MAISTERDOMES MAJESTICNESS MALAPERTNESS MALAPROPISTS MALEFACTRESS MALPOSITIONS MAMMALOGISTS MANDOLINISTS MANGALSUTRAS MANIFESTANTS MANIFESTNESS MARCATISSIMO MARGINALISTS MARQUESSATES MARQUISETTES MARTINETISMS MASCULINISTS MASSOTHERAPY MASTECTOMIES MASTERLINESS MASTERPIECES MASTERSINGER MASTERSTROKE MASTICATIONS MASTURBATORS MATERIALISES MATERIALISMS MATERIALISTS MATERIALNESS MATERNALISMS MATHEMATISES MATRONLINESS MATURENESSES MAYSTERDOMES MEADOWSWEETS MEASUREMENTS MEDIATRESSES MEDIEVALISTS MEGALOBLASTS MEGASTARDOMS MELANOBLASTS MELANOSITIES MEMORIALISTS MENSURATIONS MESOGASTRIUM MESOGNATHIES MESOGNATHISM MESOGNATHOUS MESOTHORACES MESOTHORAXES METACARPUSES METAPHORISTS METAPSYCHICS METASEQUOIAS METASOMATISM METASTASISED METASTASISES METASTASIZED METASTASIZES METATARSUSES METATHESISED METATHESISES METATHESIZES METROSEXUALS MIDDENSTEADS MIDSHIPMATES MILITANTNESS MILQUETOASTS MINIATURISES MINIATURISTS MINICASSETTE MISADJUSTING MISALLOCATES MISANTHROPES MISANTHROPOS MISBESTOWALS MISCANTHUSES MISCEGENATES MISCELLANIST MISCHANCIEST MISCITATIONS MISCREATIONS MISERABILIST MISERABLISTS MISESTIMATED MISESTIMATES MISEVALUATES MISLOCATIONS MISRELATIONS MISSTATEMENT MISSUMMATION MISTAKENNESS MISTRANSLATE MISTREADINGS MODERATENESS MOLESTATIONS MONASTICISMS MONOCRYSTALS MONOLATRISTS MONOTASKINGS MULTIFLASHES MULTITASKERS MUSCULATIONS MUSCULATURES MUSICALITIES MUSSITATIONS MUTATIONISTS MUTESSARIFAT MUTUALNESSES MYCOPHAGISTS MYOGRAPHISTS MYSTAGOGUSES MYSTICALNESS NATIONALISMS NEMATOBLASTS NEOVITALISMS NIMBOSTRATUS NITROSAMINES NOTAPHILISMS NOUMENALISTS NUMISMATISTS OBSCURANTISM ONOMASTICONS OPHTHALMISTS ORGANISTRUMS ORIENTALISMS ORNAMENTISTS OSMOLALITIES OSMOLARITIES OSTEOSARCOMA OSTRACODERMS PANENTHEISMS PANSPERMISTS PANTOMIMISTS PARABAPTISMS PARAMASTOIDS PARAMETRISES PASSAMENTING PASSEMENTING PASTORALISMS PATERNALISMS PATRISTICISM PEDANTICISMS PENTAMERISMS PHAGOCYTISMS PHOTOMOSAICS PHYTOPLASMAS PLAGIOSTOMES PLASMOSOMATA PLASTOGAMIES PLASTOMETERS POLYAMORISTS POLYMASTISMS POSTORGASMIC PRAGMATISERS PRESAGEMENTS PRIMATESHIPS PROGNATHISMS PROTAGONISMS PSAMMOPHYTES RATIONALISMS REACTIONISMS REASSESSMENT REASSIGNMENT REASSORTMENT REASSUMPTION RELATIONISMS RELEASEMENTS REMONSTRANTS REMONSTRATES RESTATEMENTS RESTIMULATES RETRANSFORMS RHEUMATEESES ROMANTICISES ROMANTICISMS ROMANTICISTS SABERMETRICS SACRAMENTALS SALINOMETERS SALTATIONISM SALTIMBANCOS SALTIMBOCCAS SALVATIONISM SANCTIMONIES SAPROPHYTISM SARCOMATOSES SARCOMATOSIS SATELLITIUMS SCAMBAITINGS SCAPEGOATISM SCATTERGRAMS SCHEMATISING SCHISMATICAL SCHISMATISED SCHISMATISES SCHISMATIZED SCHISMATIZES SCHISTOSOMAL SCHMALTZIEST SCHOOLMASTER SCITAMINEOUS SCOUTMASTERS SCYPHISTOMAE SCYPHISTOMAS SEAMSTRESSES SECTARIANISM SECTIONALISM SEISMONASTIC SEMANTICISTS SEMATOLOGIES SEMIABSTRACT SEMIBASEMENT SEMICOMATOSE SEMIFINALIST SEMIMONASTIC SEMIMYSTICAL SEMINALITIES SEMIOTICIANS SEMIPARASITE SEMITRAILERS SENSATIONISM SEPTICAEMIAS SHAMATEURISM SHOWMANLIEST SHUNAMITISMS SILLIMANITES SIMILARITIES SIMULCASTING SIMULTANEOUS SIMVASTATINS SITUATIONISM SLACKTIVISMS SLIPSTREAMED SMALLCLOTHES SMARTWATCHES SOLARIMETERS SOLMISATIONS SOLMIZATIONS SOMAESTHESIA SOMAESTHESIS SOMAESTHETIC SOMATOLOGIES SOMATOLOGIST SOMATOMEDINS SOMATOPLASMS SOMATOSTATIN SOMATOTENSIC SOMATOTONIAS SOMATOTONICS SOMERSAULTED SOMESTHESIAS SOMNAMBULIST SPASMOLYTICS SPECTROGRAMS SPELAEOTHEMS SPERMAPHYTES SPERMATHECAS SPIRITUALISM SQUAMOSITIES STABLISHMENT STACTOMETERS STADIOMETERS STAKHANOVISM STAKTOMETERS STALLMASTERS STANDPATTISM STARTLEMENTS STEAMFITTERS STEAMINESSES STEAMROLLERS STEATOMATOUS STEELMAKINGS STEGANOGRAMS STENTMASTERS STEPFAMILIES STERCORANISM STIGMASTEROL STIGMATISERS STIGMATISING STIGMATIZERS STIMULANCIES STIMULATIONS STIMULATIVES STOMACHACHES STOMATITIDES STOMATITISES STONEMASONRY STRABISMICAL STRABISMUSES STRABOMETERS STRABOTOMIES STREAMLINERS STRETCHMARKS STRIPPAGRAMS SUBBASEMENTS SUBDOMINANTS SUBFRAGMENTS SUBLIMATIONS SUFFUMIGATES SUMATRIPTANS SUMMERSAULTS SUPERMARKETS SUPERSTARDOM SUPERSTRATUM SUPREMACISTS SUPREMATISMS SUPREMATISTS SURBASEMENTS SUSTAINMENTS SYCOPHANTISM SYMMETALISMS SYMMETALLISM SYMPATHETICS SYMPATHISERS SYMPATHISING SYMPATHIZERS SYMPTOMATISE SYNAPTOSOMAL SYNAPTOSOMES SYNDACTYLISM SYSTEMATICAL SYSTEMATISED SYSTEMATISER SYSTEMATISES SYSTEMATISMS SYSTEMATISTS SYSTEMATIZED SYSTEMATIZER SYSTEMATIZES SYSTEMICALLY TAMEABLENESS TAMELESSNESS TAPHONOMISTS TASKMISTRESS TAUTOLOGISMS TAUTOMERISMS TAXIDERMISES TAXIDERMISTS TEETOTALISMS TELEMESSAGES TEMPORALISES TEMPORALNESS TESTIMONIALS TETRAMERISMS TETRATHEISMS THALASSAEMIA THALASSAEMIC THALASSEMIAS THALASSEMICS THEATRICISMS THEOMACHISTS THIRDSTREAMS TIMEPLEASERS TOASTMASTERS TRANSAMINASE TRANSFORMERS TRANSFORMISM TRANSFORMIST TRANSHUMANTS TRANSMISSION TRANSMISSIVE TRANSMITTALS TRANSMITTERS TRANSVESTISM TROMBIDIASES TROMBIDIASIS TROPHOPLASMS TRUCKMASTERS TRYPANOSOMES TYMPANITESES TYMPANITISES ULTIMATENESS UNSYMPATHIES UNSYSTEMATIC VASECTOMISED VASECTOMISES VASECTOMIZES VIGILANTISMS VOLUNTARISMS WHARFMASTERS WHATSERNAMES WHATSHISNAME WHATSISNAMES WHATSITSNAME WHOREMASTERS WRECKMASTERS