There are 418 fifteen-letter words containing A, C, I, O and U, https://www.bestwordlist.com/c/a/5/15letterwordswithaciou.htm ACCOUNTANTSHIPS ACCULTURATIONAL ACRIMONIOUSNESS AGRANULOCYTOSIS ALUMINOSILICATE AMARYLLIDACEOUS ANACOLUTHICALLY ANDROMONOECIOUS ANFRACTUOSITIES ANTICONVULSANTS ANTICONVULSIVES ANTIEDUCATIONAL ANTIFORECLOSURE ANTISPECULATION ANTITUBERCULOUS ARBORICULTURIST ASCLEPIADACEOUS ASTRONAUTICALLY ATROCIOUSNESSES AUDACIOUSNESSES AUDIOMETRICALLY AUDIOMETRICIANS AUTHENTICATIONS AUTOCORRELATION AUTODESTRUCTING AUTODESTRUCTIVE AUTODIDACTICISM AUTOGRAPHICALLY AUTOINOCULATION AUTOMORPHICALLY AUTOSCHEDIASTIC AUTOSCHEDIAZING AUTOTROPHICALLY BACTERIOPHAGOUS BASIDIOMYCETOUS BEAUTIFICATIONS BIOACCUMULATING BIOACCUMULATION BIOACOUSTICIANS BIOASTRONAUTICS BIOEQUIVALENCES BRACHIOSAURUSES CAPACIOUSNESSES CAPRIFOLIACEOUS CARDIOPULMONARY CARNIVOROUSNESS CENTRIFUGATIONS CENTUPLICATIONS CHEMAUTOTROPHIC CHENOPODIACEOUS CHONDROCRANIUMS CIRCULARISATION CIRCULARIZATION CIRCUMAMBAGIOUS CIRCUMAMBULATOR CIRCUMFORANEOUS CIRCUMGYRATIONS CIRCUMNAVIGATOR CIRCUMNUTATIONS CIRCUMVALLATION CLAUSTROPHILIAS CLAUSTROPHOBIAS CLEISTOGAMOUSLY COAGULABILITIES COEDUCATIONALLY COINSTANTANEOUS COLLOQUIALITIES COLOURABILITIES COLOURISTICALLY COMMENSURATIONS COMMUNALISATION COMMUNALIZATION COMMUNICABILITY COMMUNICATIONAL COMMUNICATIVELY COMMUNISTICALLY COMMUTABILITIES COMMUTATIVITIES COMPUTABILITIES COMPUTATIONALLY COMPUTERISATION COMPUTERIZATION COMPUTERPHOBIAS CONCEPTUALISERS CONCEPTUALISING CONCEPTUALISTIC CONCEPTUALITIES CONCEPTUALIZERS CONCEPTUALIZING CONDUPLICATIONS CONFIGURATIONAL CONFUSABILITIES CONGLOBULATIONS CONGLUTINATIONS CONGRATULATIONS CONJUGATIONALLY CONJUNCTIONALLY CONNATURALISING CONNATURALITIES CONNATURALIZING CONSANGUINITIES CONSEQUENTIALLY CONSERVATORIUMS CONSTITUTIONALS CONSUBSTANTIATE CONSULTANTSHIPS CONTEXTUALISING CONTEXTUALIZING CONTINUALNESSES CONTRAPUNTALIST CONTRARIOUSNESS CONVULSIONARIES CORPUSCULARIANS CORYNEBACTERIUM COTRANSDUCTIONS COULOMETRICALLY COUNTERACTIVELY COUNTERADAPTIVE COUNTERCAMPAIGN COUNTERCHANGING COUNTERCHARGING COUNTERCHARMING COUNTERCLAIMANT COUNTERCLAIMING COUNTERCYCLICAL COUNTERFEISANCE COUNTERGUERILLA COUNTERINSTANCE COUNTERINVASION COUNTERIRRITANT COUNTERMARCHING COUNTERPLANNING COUNTERPLEADING COUNTERRALLYING COUNTERREACTION COUNTERSHADINGS COUNTERSTAINING COUNTERVAILABLE CUSTOMARINESSES CYTOMEGALOVIRUS DECARBURISATION DECARBURIZATION DECASUALISATION DECASUALIZATION DECOLOURISATION DECOLOURIZATION DECOMMUNISATION DECOMMUNIZATION DECONTEXTUALISE DECONTEXTUALIZE DEFLOCCULATIONS DEMULSIFICATION DISARTICULATION DISARTICULATORS DISCOLOURATIONS DISCOMBOBULATED DISCOMBOBULATES DISCONTINUANCES DISCONTINUATION DISCOUNTENANCED DISCOUNTENANCES DISCOURAGEMENTS DOCUMENTARISING DOCUMENTARIZING DOCUMENTATIONAL DOLICHOSAURUSES EBULLIOSCOPICAL EBURNIFICATIONS ECHINODERMATOUS EDUCATIONALISTS EFFICACIOUSNESS ELECTROACOUSTIC ELECTROSURGICAL EMULSIFICATIONS ENTEROBACTERIUM EQUIPONDERANCES EQUIVOCALNESSES EUDAEMONISTICAL EUDIOMETRICALLY EUTROPHICATIONS EXCLAUSTRATIONS EXCOMMUNICATING EXCOMMUNICATION EXCOMMUNICATIVE EXCOMMUNICATORS EXCOMMUNICATORY FACETIOUSNESSES FLAVOURDYNAMICS FRACTIOUSNESSES FRUCTIFICATIONS FUGACIOUSNESSES FUNCTIONALISTIC FUNCTIONALITIES FURACIOUSNESSES GRANDILOQUENCES HAEMOGLOBINURIC HALLUCINATIONAL HALLUCINOGENICS HAMAMELIDACEOUS HORTICULTURALLY HUMIDIFICATIONS HYPERFUNCTIONAL ICHTHYOSAURIANS ICHTHYOSAURUSES IMMUNOGENETICAL IMMUNOGENICALLY IMMUNOLOGICALLY IMMUNOREACTIONS INARTICULATIONS INCAPACIOUSNESS INCOMMENSURABLE INCOMMENSURABLY INCOMMUNICATIVE INCOMMUTABILITY INCOMPUTABILITY INCONSEQUENTIAL INEFFICACIOUSLY INOCULABILITIES INSURRECTIONARY INTERJACULATORY INTEROSCULATING INTEROSCULATION LACTIFEROUSNESS LEUCAEMOGENESIS LEUCOCYTHAEMIAS LEUCOCYTOPENIAS LEUKOCYTOPENIAS LISSENCEPHALOUS MACROEVOLUTIONS MACROPRUDENTIAL MACROSPORANGIUM MALFUNCTIONINGS MALICIOUSNESSES MASCULINISATION MASCULINIZATION MENISPERMACEOUS MERCAPTOPURINES MESATICEPHALOUS MICROEARTHQUAKE MICROPULSATIONS MICROSPORANGIUM MICROSTRUCTURAL MINICALCULATORS MISARTICULATION MISCALCULATIONS MISCELLANEOUSLY MISCOMPUTATIONS MISGOVERNAUNCES MISPUNCTUATIONS MUCOSANGUINEOUS MULTIFUNCTIONAL MULTILOCATIONAL MULTINUCLEOLATE MULTIPLICATIONS MUSICALISATIONS MUSICALIZATIONS MUSICOLOGICALLY MUSICOTHERAPIES NEUROANATOMICAL NEUROBIOLOGICAL NEUROPATHICALLY NEUROPATHOLOGIC NEUROPLASTICITY NEUROPSYCHIATRY NEUROSURGICALLY NOCTAMBULATIONS NONAGRICULTURAL NONARCHITECTURE NONCOMMUNICANTS NONCULTIVATIONS NONEQUIVALENCES NONFUNCTIONALLY NONINTELLECTUAL NONMATRICULATED NONOCCUPATIONAL NUCLEARISATIONS NUCLEARIZATIONS NUCLEOPLASMATIC OBSTRUCTIONALLY ORGANOMERCURIAL OVERARTICULATED OVERARTICULATES OVERCOMMUNICATE OVERCULTIVATION OVERENCOURAGING OVERSPECULATING OVERSPECULATION OXIDOREDUCTASES PASSIFLORACEOUS PERSPICACIOUSLY PHONAUTOGRAPHIC PHOTODUPLICATED PHOTODUPLICATES PITHECANTHROPUS PLANTAGINACEOUS PLUMBAGINACEOUS PLUTOCRATICALLY PNEUMATOLOGICAL POCOCURANTEISMS POSTINOCULATION PREPUBLICATIONS PROCELEUSMATICS PROCURATORSHIPS PRONUNCIAMENTOS PRONUNCIATIONAL PSYCHOACOUSTICS PSYCHOSEXUALITY PULMOBRANCHIATE PUNCTUATIONISTS QUADRUPLICATION QUANTIFICATIONS QUATTROCENTISMS QUATTROCENTISTS QUINTUPLICATION QUIZZIFICATIONS QUODLIBETICALLY RADICULOPATHIES RAPACIOUSNESSES REARTICULATIONS RECAPITULATIONS RECONCEPTUALISE RECONCEPTUALIZE RECONFIGURATION RECONSTITUTABLE RECONTEXTUALISE RECONTEXTUALIZE RESURRECTIONARY RHEUMATOLOGICAL SAGACIOUSNESSES SALACIOUSNESSES SANCTIMONIOUSLY SANGUIFICATIONS SANGUINOLENCIES SANSCULOTTERIES SARRACENIACEOUS SCEUOPHYLACIUMS SCRIBACIOUSNESS SECULARISATIONS SECULARIZATIONS SECURITISATIONS SECURITIZATIONS SEMIDOCUMENTARY SESQUICARBONATE SHOCKUMENTARIES SOCIOCULTURALLY STRATICULATIONS STREPTOBACILLUS STULTIFICATIONS SUBASSOCIATIONS SUBCATEGORISING SUBCATEGORIZING SUBCIVILISATION SUBCIVILIZATION SUBCONTRACTINGS SUBVOCALISATION SUBVOCALIZATION SUPERCARGOSHIPS SUPERORGANICISM SUPERORGANICIST SUSPERCOLLATING TENACIOUSNESSES TENTACULIFEROUS TRAUMATOLOGICAL TUBERCULISATION TUBERCULIZATION ULTRACOMMERCIAL ULTRACONVENIENT ULTRADEMOCRATIC ULTRAMICROMETER ULTRAMICROSCOPE ULTRAMICROSCOPY ULTRAMICROTOMES ULTRAPRECISIONS UNACCOMMODATING UNAPOSTOLICALLY UNAPPRECIATIONS UNCANONICALNESS UNCATEGORISABLE UNCATEGORIZABLE UNCHRONOLOGICAL UNCOMBATIVENESS UNCOMMUNICATIVE UNCOMPANIONABLE UNCOMPASSIONATE UNCOMPLAININGLY UNCOMPLAISANTLY UNCOMPLIMENTARY UNCOMPROMISABLE UNCONDITIONALLY UNCONSTRAINABLE UNCONSTRAINEDLY UNCONTROVERSIAL UNCONVENTIONALS UNCOOPERATIVELY UNCOPYRIGHTABLE UNDOMESTICATING UNEQUIVOCALNESS UNEXCEPTIONABLE UNEXCEPTIONABLY UNEXCEPTIONALLY UNIDEOLOGICALLY UNIDIOMATICALLY UNOBJECTIONABLE UNOBJECTIONABLY UNPATRIOTICALLY UNPHILOSOPHICAL UNRECONCILIABLE UNSATISFACTIONS UNSOCIABILITIES UNSOPHISTICATED VASCULARISATION VASCULARIZATION VERACIOUSNESSES VICARIOUSNESSES VIVACIOUSNESSES VORACIOUSNESSES VOYEURISTICALLY WATERCOLOURISTS