There are 438 fourteen-letter words containing A, O and 3S, https://www.bestwordlist.com/c/a/5/14letterwordswithaosss.htm
ABORTIVENESSES ABSOLUTENESSES ABSORPTIVENESS ABSTEMIOUSNESS ABSTENTIONISMS
ABSTENTIONISTS ACCUSTOMEDNESS ADORABLENESSES AGROBUSINESSES AGROSTOLOGISTS
ALDOSTERONISMS AMBASSADORSHIP AMPHIBIOUSNESS ANARTHROUSNESS ANKYLOSAURUSES
ANTISOCIALISMS ANTISOCIALISTS ANTISPASMODICS APPOSITENESSES ARISTOCRATISMS
ASSASSINATIONS ASSOCIATESHIPS ASSOCIATIONISM ASSOCIATIONIST ASSORTEDNESSES
ASTHENOSPHERES ASTROCOMPASSES ASTROPHYSICIST AUDIOCASSETTES AUSPICIOUSNESS
AUTOSCHEDIASMS AVARICIOUSNESS AVOWABLENESSES BACTERIOSTASES BACTERIOSTASIS
BALLISTOSPORES BASIDIOSPOROUS BIOSYSTEMATICS BIOSYSTEMATIST BLEPHAROSPASMS
BOARDERCROSSES BOASTFULNESSES BOUILLABAISSES BRASSFOUNDINGS BREASTSTROKERS
BRONTOSAURUSES CADAVEROUSNESS CAESAROPAPISMS CALAMITOUSNESS CANOROUSNESSES
CAPRICIOUSNESS CAPTIOUSNESSES CASUALISATIONS CATASTROPHISMS CATASTROPHISTS
CAUTIOUSNESSES CHIAROSCURISMS CHIAROSCURISTS CHIVALROUSNESS COENAESTHESIAS
COETANEOUSNESS COLONIALNESSES COLOURFASTNESS COMMISSARYSHIP COMPASSIONATES
COMPASSIONLESS CONSTABLESHIPS CONTAGIOUSNESS CONTRABASSISTS CONTRABASSOONS
CONTRARINESSES COSMOGRAPHISTS COURAGEOUSNESS COWARDLINESSES CRANIOSCOPISTS
CROSSABILITIES CROSSHATCHINGS CURVACEOUSNESS CURVACIOUSNESS CUSTODIANSHIPS
CUSTOMISATIONS CYSTOLITHIASES CYSTOLITHIASIS DEBONAIRNESSES DEPERSONALISES
DESERTISATIONS DESOLATENESSES DESPOTICALNESS DIAPHANOUSNESS DIESELISATIONS
DILATORINESSES DISASSOCIATING DISASSOCIATION DISESTIMATIONS DISIMPASSIONED
DISPENSATORIES DISPOSABLENESS DISSEMINATIONS DISSEVERATIONS DISSIMILATIONS
DISSIMULATIONS DISSOCIALISING DISSOCIALITIES DOWNWARDNESSES EDACIOUSNESSES
ENCOMPASSMENTS ENHYPOSTATISES ESCHATOLOGISTS ESCHSCHOLTZIAS ESOPHAGOSCOPES
EXTRANEOUSNESS FABULOUSNESSES FACINOROUSNESS FACTIOUSNESSES FACTITIOUSNESS
FALLACIOUSNESS FASHIOUSNESSES FASTIDIOUSNESS FATHOMLESSNESS FAVOUREDNESSES
FEARSOMENESSES FETISHISATIONS FLAGITIOUSNESS FORNICATRESSES FORSAKENNESSES
FOSSILISATIONS FOSSILIZATIONS FOURSQUARENESS GALACTOSIDASES GAMESOMENESSES
GASTROPLASTIES GASTROSCOPISTS GELATINOUSNESS GENERALISSIMOS GEOSTRATEGISTS
GLABROUSNESSES GLADSOMENESSES GLAMOUROUSNESS GLAUCOUSNESSES GLOBULARNESSES
GLOSSOGRAPHERS GLOSSOGRAPHIES GRACIOUSNESSES GRATUITOUSNESS GREGARIOUSNESS
HALLOWEDNESSES HANDSOMENESSES HARMONIOUSNESS HEADSTRONGNESS HEROICALNESSES
HETEROGLOSSIAS HISTOPLASMOSES HISTOPLASMOSIS HISTORICALNESS HOMOSEXUALISMS
HOMOSEXUALISTS HOSPITABLENESS IDIOSYNCRASIES IDOLATROUSNESS IGNORANTNESSES
IMMUNOASSAYIST IMPERSONALISES INAPPOSITENESS INCAUTIOUSNESS INCHOATENESSES
INFAMOUSNESSES INTROGRESSANTS IRONICALNESSES ISOMERISATIONS JOHNSONGRASSES
KNOWABLENESSES LABOUREDNESSES LANGUOROUSNESS LANUGINOUSNESS LAPAROSCOPISTS
LASCIVIOUSNESS LOATHFULNESSES LOQUACIOUSNESS LOVEABLENESSES MALODOROUSNESS
MANIFOLDNESSES MARVELLOUSNESS MASSIFICATIONS MASSOTHERAPIES MASSOTHERAPIST
MATRONLINESSES MENDACIOUSNESS MESMERISATIONS MESOCEPHALISMS MICROCASSETTES
MIRACULOUSNESS MISANTHROPISTS MISANTHROPOSES MISASSUMPTIONS MISESTIMATIONS
MISOBSERVANCES MISPERSUASIONS MISSIONARISING MISSIONISATION MODERATENESSES
MONOGAMOUSNESS MONOSYLLABISMS MORDACIOUSNESS MOVEABLENESSES NARCOSYNTHESES
NARCOSYNTHESIS NAUSEOUSNESSES NECESSITATIONS NECTAREOUSNESS NEGOTIATRESSES
NEOCLASSICISMS NEOCLASSICISTS NEOPLASTICISMS NEOPLASTICISTS NONAGGRESSIONS
NONCLASSIFIEDS NONRESISTANCES NONSPECIALISTS NUGATORINESSES OBDURATENESSES
OBSERVABLENESS OCCASIONALISMS OCCASIONALISTS OESOPHAGITISES OLEAGINOUSNESS
OMBUDSMANSHIPS OMPHALOSKEPSES OMPHALOSKEPSIS OPISTHOGLOSSAL ORACULARNESSES
ORCHARDGRASSES ORCHESTRALISTS ORDINARINESSES OSTEOARTHROSES OSTEOARTHROSIS
OUTDATEDNESSES OUTLANDISHNESS OUTRAGEOUSNESS OVERASSERTIONS OVERASSESSMENT
OVERCLASSIFIES OVEREMPHASISES OVERRASHNESSES PASSIONATENESS PASSIONFLOWERS
PASTORALNESSES PATULOUSNESSES PERISSODACTYLS PERSONABLENESS PHOSPHOKINASES
PHOSPHOLIPASES PHOSPHORYLASES PHRASEOLOGISTS PLESIOSAURIANS PODSOLISATIONS
POETICALNESSES POLYSYLLABISMS POSSESSIONATES POSTERISATIONS POSTLAPSARIANS
POSTMASTERSHIP POSTULANTSHIPS PRECARIOUSNESS PREDACEOUSNESS PREDACIOUSNESS
PRESSURISATION PROFESSORIATES PROSOPAGNOSIAS PROVABLENESSES PSEPHOANALYSES
PSEPHOANALYSIS PSEUDARTHROSES PSEUDARTHROSIS PSEUDOCLASSICS PSYCHOANALYSES
PSYCHOANALYSIS PSYCHOANALYSTS PSYCHOPATHISTS PSYCHOSOMATICS PUGNACIOUSNESS
QUOTABLENESSES RADIOSENSITISE RAMPAGEOUSNESS RATIONALNESSES RAVENOUSNESSES
REASONABLENESS RECESSIONISTAS REHOSPITALISES RESOLVABLENESS RESTORABLENESS
RESUSCITATIONS RETRANSMISSION SACERDOTALISES SACERDOTALISMS SACERDOTALISTS
SACRALISATIONS SACROILIITISES SACROSANCTNESS SADOMASOCHISMS SADOMASOCHISTS
SALPIGLOSSISES SALUBRIOUSNESS SANITATIONISTS SANSCULOTTIDES SANSCULOTTISMS
SANSCULOTTISTS SCABROUSNESSES SCANDALOUSNESS SCAPEGALLOWSES SCENARISATIONS
SCHOLASTICATES SCHOLASTICISMS SEASONABLENESS SEASONALNESSES SECTORISATIONS
SEISMOGRAPHERS SEISMOGRAPHIES SEMASIOLOGISTS SEMICONSONANTS SENSATIONALISE
SENSATIONALISM SENSATIONALIST SENSITISATIONS SENSITIZATIONS SENSUALISATION
SEPARATIONISMS SEPARATIONISTS SEQUACIOUSNESS SEQUESTRATIONS SERIALISATIONS
SEXUALISATIONS SHADOWCASTINGS SHARPSHOOTINGS SIGNALISATIONS SIMULTANEOUSES
SINANTHROPUSES SINISTRORSALLY SLANDEROUSNESS SNOWBOARDCROSS SOCIABLENESSES
SOCIALISATIONS SOFTHEADEDNESS SOLEMNISATIONS SOLIFIDIANISMS SOLITARINESSES
SOLVABLENESSES SOMAESTHESISES SOPHISTICATORS SORBITISATIONS SOREHEADEDNESS
SOUTHEASTWARDS SOUTHWESTWARDS SOVIETISATIONS SPACIOUSNESSES SPARROWGRASSES
SPECTATORSHIPS SPELAEOLOGISTS SPERMATOBLASTS SPHAGNOLOGISTS SPIROCHAETOSES
SPIROCHAETOSIS SPOKESMANSHIPS SPORADICALNESS SPORTSMANLIEST SPORTSMANSHIPS
SQUAMOSENESSES SQUAMOUSNESSES STABILISATIONS STATIONARINESS STATIONMASTERS
STENOGRAPHISTS STERILISATIONS STERNOMASTOIDS STOMACHFULNESS STOMATOLOGISTS
STONEMASONRIES STREPTOKINASES STROPHANTHUSES SUBADOLESCENTS SUBASSOCIATION
SUBCATEGORISES SUBDEACONSHIPS SUBSATURATIONS SUBSIDISATIONS SUBSIDIZATIONS
SUBSPONTANEOUS SUBSTANTIATORS SUBTILISATIONS SUCCESSIONALLY SULFURISATIONS
SUMMARISATIONS SUPERLOYALISTS SUPERORGANISMS SURROGATESHIPS SUSPERCOLLATES
SWORDSMANSHIPS SYLLOGISATIONS SYMBOLICALNESS SYMBOLISATIONS SYNAPOSEMATISM
SYNCHROFLASHES SYNTHESISATION SYPHILISATIONS SYSTEMISATIONS SYSTEMIZATIONS
TACHISTOSCOPES TEMPORALNESSES THOROUGHBASSES TOPOISOMERASES TOWARDLINESSES
TRAITOROUSNESS TRANSFUSIONIST TRANSGRESSIONS TRANSISTORISED TRANSISTORISES
TRANSISTORIZES TRANSITORINESS TRANSMISSIONAL TRANSPOSITIONS UMBRAGEOUSNESS
UNGRACIOUSNESS UNHANDSOMENESS UNSAVORINESSES UNSEASONEDNESS UNSOCIABLENESS
UNTOWARDNESSES UPROARIOUSNESS VAPORISHNESSES VAPOROUSNESSES VIDEOCASSETTES
VILLAINOUSNESS VIOLABLENESSES VISUALISATIONS VIVIPAROUSNESS VOIDABLENESSES
VOLATILENESSES WOMANISHNESSES WORKABLENESSES