There are 537 eleven-letter words containing 2A, 2I and S, https://www.bestwordlist.com/c/a/5/11letterwordswithaaiis.htm
ABDICATIONS ABIRRITANTS ABIRRITATES ABLATITIOUS ABORIGINALS ACADEMICISM
ACCLIMATISE ACETANILIDS ACIERATIONS ACOUSTICIAN ACRIFLAVINS ACTIVATIONS
ACTUALISING ACTUALITIES ADIAPHORISM ADIAPHORIST ADMIRALSHIP ADMIRALTIES
ADMIRATIONS ADOPTIANISM ADOPTIANIST ADRIAMYCINS ADVENTITIAS AERIALITIES
AESTIVATING AESTIVATION AFFIXATIONS AFICIONADAS AFICIONADOS AGONISTICAL
AGRARIANISM AHISTORICAL AIRMANSHIPS ALCAICERIAS ALIENATIONS ALINEATIONS
ALITERACIES ALKALINISED ALKALINISES ALKALINIZES ALLIGATIONS ALLOCHIRIAS
AMORALITIES AMPHISCIANS AMPLIATIONS ANADIPLOSIS ANAGNORISIS ANALOGISING
ANARCHISING ANARCHISTIC ANATOMISING ANCILLARIES ANIMALISING ANIMALISTIC
ANIMALITIES ANISEIKONIA ANISOGAMIES ANNIHILATES ANNUALISING ANODISATION
ANOMALISTIC ANTICIPANTS ANTICIPATES ANTICLASTIC ANTICLINALS ANTIFASCISM
ANTIFASCIST ANTIFASHION ANTIMONIALS ANTIMUSICAL ANTINOMIANS ANTIPARTIES
ANTIPATHIES ANTIPATHIST ANTIPHRASIS ANTIQUARIES ANTIRACISMS ANTIRACISTS
ANTIREALISM ANTIREALIST ANTISOCIALS ANTISPASTIC ANTISTATICS ANTISTATIST
ANTITARNISH APHRODISIAC APHRODISIAS APPARITIONS APRICATIONS AQUATINTIST
ARABICISING ARABILITIES ARABINOSIDE ARABISATION ARCHAICISMS ARMILLARIAS
AROMATISING ARRAIGNINGS ARRIVANCIES ARTERIALISE ARTISANSHIP ASPIDISTRAS
ASPIRATIONS ASSEGAAIING ASSIBILATED ASSIBILATES ASSIGNATION ASSIMILABLE
ASSIMILABLY ASSIMILATED ASSIMILATES ASSIMILATOR ASSOCIATING ASSOCIATION
ASSOCIATIVE ASTATICISMS ASTERIDIANS ASTIGMATICS ASTIGMATISM ATHEISTICAL
ATOMISATION ATOMISTICAL ATONALITIES ATRABILIOUS AUDIOVISUAL AUSPICATING
AUXILIARIES AXIOMATISED AXIOMATISES AXIOMATIZES BACILLEMIAS BACILLURIAS
BACITRACINS BALANITISES BALKANISING BARBARISING BARBARITIES BARGAININGS
BASICRANIAL BASIDIOCARP BASOPHILIAS BASTINADING BEAUTICIANS BIOASSAYING
BIPARTISANS BIPINNARIAS BIRACIALISM CABBALISTIC CAIPIRINHAS CANDIDACIES
CANDIDIASES CANDIDIASIS CANNIBALISE CANNIBALISM CANOPHILIAS CAPILLAIRES
CAPILLARIES CAPITALISED CAPITALISES CAPITALISMS CAPITALISTS CAPITALIZES
CAPITATIONS CAPTAINCIES CAPTAINRIES CAPTAINSHIP CARABINIERS CARDIALGIAS
CARDIALGIES CARNALISING CARNALITIES CASTABILITY CASTIGATING CASTIGATION
CASUALISING CASUALIZING CASUISTICAL CATHARISING CAUSABILITY CAUSALITIES
CAVALIERISH CAVALIERISM CAVITATIONS CHAINSAWING CHARISMATIC CHINACHINAS
CHRISTIANIA CICATRISANT CIRCASSIANS CISATLANTIC COULIBIACAS CREATIANISM
CULINARIANS DAMASKINING DERACIALISE DIACAUSTICS DIAGONALISE DIALYSATION
DIASTEMATIC DIATHERMIAS DICHASIALLY DIGLADIATES DILAPIDATES DILATANCIES
DILATATIONS DINOSAURIAN DIPSOMANIAC DIPSOMANIAS DISACCHARID DISANIMATED
DISANIMATES DISARRAYING DISPARAGING DIVAGATIONS DIVARICATES DRAMATICISM
DRAMATISING EMACIATIONS EPIGASTRIAL ERADIATIONS ERASABILITY FACILITATES
FAINEANCIES FAINEANTISE FALSIFIABLE FAMILIARISE FANATICISED FANATICISES
FANATICISMS FANATICIZES FANTASISING FANTASIZING FASCIATIONS FASCINATING
FASCINATION FASCINATIVE FASHIONISTA FASTIGIATED FIANCAILLES FRANGIPANIS
FRUITARIANS FUSTILARIAN GAILLARDIAS GAINSAYINGS GAINSHARING GALLIAMBICS
GALLIARDISE GALVANISING GARGARISING GLACIALISTS GLACIATIONS HABILITATES
HABITATIONS HAEMATINICS HAGGADISTIC HAGIARCHIES HEMIANOPIAS HEMIANOPSIA
HEMICRANIAS HISPANIDADS HISTAMINASE ICOSANDRIAN IMAGINARIES IMMANATIONS
IMPANATIONS IMPARADISED IMPARADISES IMPASTATION INACTIVATES INADVISABLE
INADVISABLY INCAPACIOUS INDAGATIONS INDAPAMIDES INGRATIATES INHABITANTS
INHALATIONS INMARRIAGES INSALIVATED INSALIVATES INSATIATELY INSTANTIATE
INVAGINATES INVALIDATES INVARIABLES INVARIANCES IPSILATERAL IRRADIANCES
IRRADIATORS IRRADICATES IRRATIONALS ISALLOBARIC ITALIANATES ITALIANISED
ITALIANISES ITALIANIZES JAMAHIRIYAS JANISSARIES JUBILARIANS KABBALISTIC
KOULIBIACAS KOWHAIWHAIS KYANISATION LABIALISING LABIALITIES LACRIMARIES
LAICISATION LAMINARIANS LAMINARISED LAMINARISES LAMINARIZES LAMINATIONS
LAPIDARISTS LAPIDATIONS LATITANCIES LATITATIONS LAYMANISING LEISHMANIAE
LEISHMANIAL LEISHMANIAS LIMITARIANS MADRIGALIST MAGAZINISTS MAGISTERIAL
MAGISTRATIC MAGNIFICATS MAIDENHAIRS MAINTAINERS MAINTOPSAIL MAMMALITIES
MANDARINISM MANORIALISM MARGINALISE MARGINALISM MARGINALIST MARINATIONS
MARMALISING MARMARISING MARTIALISMS MARTIALISTS MASTICATING MASTICATION
MATERIALISE MATERIALISM MATERIALIST MAXILLARIES MAXIMALISTS MAXIMATIONS
MEDIASTINAL MIASMATICAL MIASMICALLY MIDSAGITTAL MISADAPTING MISALLIANCE
MISANALYSIS MISASSAYING MISAWARDING MISCARRIAGE MISMANAGING MISMARRIAGE
NANISATIONS NANIZATIONS NATIONALISE NATIONALISM NATIONALIST NAVIGATIONS
PACIFICATES PAEDIATRICS PAEDIATRIES PAEDIATRIST PAGINATIONS PAINSTAKING
PALINOPSIAS PALISADOING PALLIATIONS PALLIATIVES PANARITIUMS PANISLAMIST
PARADISICAL PARAKITINGS PARALEIPSIS PARAPHILIAS PARAPHILICS PARASAILING
PARASITICAL PARASITISED PARASITISES PARASITISMS PARASITIZED PARASITIZES
PARASITOIDS PARASITOSIS PARASKIINGS PARASUICIDE PAREIDOLIAS PARMACITIES
PARMIGIANOS PARTIALISED PARTIALISES PARTIALISMS PARTIALISTS PARTIALIZES
PASIGRAPHIC PASSIVATING PASSIVATION PATINATIONS PATRIALISED PATRIALISES
PATRIALISMS PATRIALIZES PATRIATIONS PATRICIATES PATRISTICAL PERSICARIAS
PHARISAICAL PHARISAISMS PISCATORIAL PISCIFAUNAE PISCIFAUNAS PLAGIARISED
PLAGIARISER PLAGIARISES PLAGIARISMS PLAGIARISTS PLAGIARIZES PLANARITIES
PLASTILINAS PLEIOCHASIA PRACTICIANS PRISMATICAL QUINAQUINAS RACIALISING
RACIALISTIC RADIALISING RADIALITIES RADICALISED RADICALISES RADICALISMS
RADICALIZES RADICATIONS RAINMAKINGS RAINWASHING RAIYATWARIS RASCALITIES
RATIONALISE RATIONALISM RATIONALIST REALISATION REASSAILING RHINOLALIAS
SABBATISING SABBATIZING SACRALISING SACRALITIES SACRALIZING SACRIFICIAL
SACROILIACS SAGINATIONS SAGITTARIES SAILBOATING SAILMAKINGS SAILPLANING
SAINTPAULIA SALEABILITY SALICIONALS SALICORNIAS SALIENTIANS SALIVATIONS
SALVABILITY SANGUINARIA SANITARIANS SANITARISTS SANITARIUMS SANITATIONS
SANSEVIERIA SAQUINAVIRS SATIABILITY SATIRICALLY SATIRISABLE SATIRIZABLE
SATISFIABLE SAURISCHIAN SCALABILITY SCAMBAITING SCIAMACHIES SEMIAQUATIC
SEMINARIANS SEPTICAEMIA SHAMANISTIC SHANGHAIING SIGILLARIAN SIMVASTATIN
SINUPALLIAL SITUATIONAL SKIAMACHIES SOLITARIANS SOPAIPILLAS SPATIALISED
SPATIALISES SPATIALIZED SPATIALIZES STAIRCASING STALACTITIC STALAGMITIC
STATISTICAL STIACCIATOS STIGMARIANS STIGMATICAL STRAVAIGING SUBIMAGINAL
SYBARITICAL TAENIACIDES TAGLIARINIS TAILGATINGS TANTALISING TARTARISING
THIAMINASES TILLANDSIAS TRITANOPIAS UNFAMILIARS UNSATIATING UNSATIRICAL
VACATIONIST VALIDATIONS VANADINITES VANDALISING VANDALISTIC VASSALISING
VASSALIZING VATICINATES VICARIANCES VICTORIANAS VILLAINAGES WASHABILITY
WASSAILINGS WASSAILRIES ZAMINDARIES