There are 444 thirteen-letter words containing A, M, S, T and U, https://www.bestwordlist.com/c/a/5/13letterwordswithamstu.htm ACCOUCHEMENTS ACCOUPLEMENTS ACCOUSTREMENT ACCOUTERMENTS ACCOUTREMENTS ACCUMULATIONS ACCUSTOMATION ACCUSTREMENTS ADMEASUREMENT ADMINICULATES ADVENTURESOME ALUMINOSITIES AMARANTACEOUS AMBIDEXTEROUS AMBISEXUALITY AMBITIOUSNESS AMINOTOLUENES AMPHIBLASTULA AMPHIGASTRIUM AMPHITRICHOUS AMPULLOSITIES ANIMALCULISTS ANNOUNCEMENTS ANTICOMMUNISM ANTICOMMUNIST ANTIHUMANISMS ANTIHUMANISTS ANTIRITUALISM ANTISMUGGLING ANTISUBMARINE ASTROTOURISMS AUDIOMETRISTS AUGMENTATIONS AUGMENTATIVES AUTOCHTHONISM AUTOCOMPLETES AUTOEROTICISM AUTOMOBILISMS AUTOMOBILISTS AUTOMORPHISMS AUTOSCHEDIASM AUTOTOXAEMIAS AYUNTAMIENTOS BEAUMONTAGUES BEQUEATHMENTS BICULTURALISM BLABBERMOUTHS BREASTSUMMERS BUREAUCRATISM CALUMNIATIONS CARCINOMATOUS CATAMOUNTAINS CATECHUMENISM CAUSATIONISMS CENTUMVIRATES CHEMOAUTROPHS CHONDROMATOUS CHORUSMASTERS CHRYSANTHEMUM CINEMATHEQUES CIRCUMGYRATES CIRCUMNUTATES CIRCUMROTATES CIRCUMSTANCED CIRCUMSTANCES CIRCUMSTELLAR CLEISTOGAMOUS COASTGUARDMAN COASTGUARDMEN COLUMNARITIES COLUMNIATIONS COMMUNALISTIC COMMUNALITIES COMMUNICATEES COMMUNICATORS COMMUNISATION COMMUNITAIRES COMPURGATIONS CONCEPTUALISM CONDYLOMATOUS CONSUMMATIONS CONTUMACITIES COSMECEUTICAL COUNTERCHARMS COUNTERCLAIMS COUNTERIMAGES COUNTERSTREAM CUMULOSTRATUS CUSTOMARINESS CUSTOMISATION CUSTOMIZATION DARMSTADTIUMS DECUMULATIONS DEMODULATIONS DEMUTUALISING DESQUAMATIONS DEUTEROGAMIES DEUTEROGAMIST DEUTEROPLASMS DIATHERMANOUS DISACCUSTOMED DISAMBIGUATED DISAMBIGUATES DISANNULMENTS DISILLUMINATE DISSIMULATING DISSIMULATION DISSIMULATIVE DISSIMULATORS DOCUMENTALIST DOCUMENTARIES DOCUMENTARISE DOCUMENTARIST DRAMATURGISTS DRAUGHTSWOMAN DRAUGHTSWOMEN EMASCULATIONS EMBARQUEMENTS EMPHYSEMATOUS EMPYREUMATISE ENTOMOPHAGOUS EPITHALAMIUMS EQUESTRIANISM EUDAEMONISTIC EUDAIMONISTIC EUROTERMINALS EXANTHEMATOUS FLAMMULATIONS FORMULARISTIC FRACTOCUMULUS FRUITARIANISM FRUMENTACEOUS FRUMENTARIOUS FRUMENTATIONS FUNAMBULATORS FUNCTIONALISM GASTROCNEMIUS GEITONOGAMOUS GRANULOMATOUS GUESSTIMATING HAEMATOGENOUS HARMONIUMISTS HELIANTHEMUMS HEMATOPHAGOUS HOMOSEXUALIST HOMOSEXUALITY HUMANISATIONS HUMANITARIANS HUMANIZATIONS HUMIFICATIONS HUNTSMANSHIPS HYDROSOMATOUS ILLUMINATIONS IMMUNISATIONS IMMUNIZATIONS IMMUTABLENESS IMPORTUNACIES IMPOSTHUMATED IMPOSTHUMATES IMPOSTUMATING IMPOSTUMATION IMPUTABLENESS INDUSTRIALISM INHALATORIUMS INSTRUMENTALS INTERMUSCULAR INTRAMUSCULAR JUSTICIALISMS KURCHATOVIUMS LANGUISHMENTS LIGHTHOUSEMAN LUMBERJACKETS MAGISTRATURES MAGNETOPAUSES MAGNITUDINOUS MALADJUSTMENT MALNUTRITIONS MANIPULATIONS MANIPULATIVES MANSLAUGHTERS MANUFACTORIES MANUFACTURERS MARICULTURIST MASCULINITIES MASTERFULNESS MASTURBATIONS MATRICULATORS MEASURABILITY MEDICAMENTOUS MEGASTRUCTURE MENSTRUATIONS MENSURABILITY MENSURATIONAL MERCURIALISTS METACOMPUTERS METALANGUAGES METALLIFEROUS METALLURGISTS METHAQUALONES MINIATURISING MINIATURISTIC MISADJUSTMENT MISADVENTURED MISADVENTURER MISADVENTURES MISARTICULATE MISASSUMPTION MISATTRIBUTED MISATTRIBUTES MISCALCULATED MISCALCULATES MISCALCULATOR MISCATALOGUED MISCATALOGUES MISEDUCATIONS MISEVALUATING MISEVALUATION MISPUNCTUATED MISPUNCTUATES MISQUOTATIONS MISSUMMATIONS MISUNDERSTAND MITRAILLEUSES MONODACTYLOUS MONOSATURATED MONOTHALAMOUS MONOTREMATOUS MONUMENTALISE MOUNTAINOUSLY MOUNTAINSIDES MOUNTEBANKISM MOUNTENAUNCES MOUSETRAPPING MOUSQUETAIRES MUCOCUTANEOUS MULTIACCESSES MULTIAGENCIES MULTICAMPUSES MULTICHANNELS MULTIFAMILIES MULTIGRAVIDAS MULTIHOSPITAL MULTIMEGATONS MULTIORGASMIC MULTIPARITIES MULTIPARTYISM MULTIPLICANDS MULTIPLICATES MULTISPECTRAL MULTISTANDARD MULTISTRANDED MULTISYLLABIC MULTITASKINGS MULTIVALENCES MULTIVITAMINS MULTIWARHEADS MULTUNGULATES MUNICIPALISTS MUSCULARITIES MUSICIANLIEST MUSICOTHERAPY MUTABLENESSES MUTESSARIFATS MUTUALISATION MYCETOPHAGOUS MYXOEDEMATOUS NEMATODIRUSES NEUROBLASTOMA NOCTAMBULISMS NOCTAMBULISTS NOMENCLATURES NOMENKLATURAS NONAUTONOMOUS NOUMENALITIES NUMISMATOLOGY OBSCURANTISMS OMMATOPHOROUS OMNISEXUALITY ORNITHOGALUMS OUTDOORSWOMAN OUTMANOEUVRES OUTPLACEMENTS OVERAMBITIOUS OVERSTIMULATE PALUDAMENTUMS PAPILLOMATOUS PARAMENSTRUUM PARAMOUNTCIES PARTICULARISM PERAMBULATORS PERIOSTRACUMS PERMACULTURES PERPETUALISMS PHARMACEUTICS PHARMACEUTIST PLAGIOSTOMOUS PNEUMATOLYSES PNEUMATOLYSIS PNEUMOGASTRIC POCOCURANTISM POLYTHALAMOUS POSTMENOPAUSE POSTMENSTRUAL POSTTRAUMATIC PREFORMULATES PREMATURENESS PREMATURITIES PROMULGATIONS PROTACTINIUMS PROTANOMALOUS PRUDENTIALISM PSEUDOMARTYRS PUSILLANIMITY QUARRYMASTERS QUARTERMASTER RADIOTHORIUMS REACCUSTOMING READJUSTMENTS REASSUMPTIONS REMEASUREMENT REMUNERATIONS RESTIMULATING RESTIMULATION SANCTIMONIOUS SANSCULOTTISM SARMENTACEOUS SCAPULIMANTIC SCAPULOMANTIC SCRIPTURALISM SEMIAUTOMATED SEMIAUTOMATIC SEMIMENSTRUAL SHAMATEURISMS SHOCKUMENTARY SITUATIONISMS SLUMPFLATIONS SOMATOPLEURAL SOMATOPLEURES SOMATOPLEURIC SOMERSAULTING SOMNAMBULANTS SOMNAMBULATED SOMNAMBULATES SOMNAMBULATOR SOMNAMBULISTS SPATHIPHYLLUM SPIRITUALISMS STAMINIFEROUS STIMULATINGLY STRATOCUMULUS STRUCTURALISM SUBDEPARTMENT SUBMINIATURES SUFFRAGETTISM SUFFUMIGATING SUFFUMIGATION SULFACETAMIDE SULFONMETHANE SUMMABILITIES SUMMARISATION SUMMARIZATION SUMMERSAULTED SUPERDIPLOMAT SUPERDOMINANT SUPERHUMANITY SUPERMAJORITY SUPERMILITANT SUPERROMANTIC SUPERSTARDOMS SUPERSTRATUMS SUPPLEMENTALS SUPPLEMENTARY SUPRATEMPORAL SURCHARGEMENT SUSTENTACULUM TAMBOURINISTS TAUROMORPHOUS TAUTOCHRONISM TEMERARIOUSLY TETRADYNAMOUS THAUMATURGICS THAUMATURGIES THAUMATURGISM THAUMATURGIST TRADUCIANISMS TRANSEXUALISM TRANSHUMANCES TRANSMOUNTAIN TRANSMUTATION TRANSMUTATIVE TRANSUMPTIONS TRAUMATONASTY TREPONEMATOUS TRILINGUALISM TRIUMPHALISMS TRIUMPHALISTS TROUBLEMAKERS TSUTSUGAMUSHI TUMULTUATIONS ULTRALEFTISMS ULTRALUMINOUS ULTRAMONTANES ULTRAREALISMS ULTRARIGHTISM UMBILICATIONS UNAMBITIOUSLY UNASSIMILATED UNATHLETICISM UNCHARISMATIC UNCOMPENSATED UNCOMPLAISANT UNCONSUMMATED UNCUSTOMARILY UNDERESTIMATE UNDERGARMENTS UNDERLAYMENTS UNDERPAYMENTS UNDERSTRATUMS UNDOMESTICATE UNICAMERALIST UNILATERALISM UNIMPORTANCES UNITARIANISMS UNMANNERLIEST UNMETABOLISED UNMINISTERIAL UNMISTAKEABLE UNMISTAKEABLY UNSENTIMENTAL UNSMOTHERABLE UNSTIGMATISED UNSTIGMATIZED UNSYMMETRICAL UNSYMPATHETIC UNTAMABLENESS UNTAMEDNESSES UNTRANSFORMED UNTRANSMITTED VANQUISHMENTS VERUMONTANUMS VOLUNTARYISMS VOUCHSAFEMENT WHATABOUTISMS XERODERMATOUS