There are 433 fifteen-letter words containing A, C, L and 2S, https://www.bestwordlist.com/c/a/5/15letterwordswithaclss.htm
ACCESSIBILITIES ACCOMPLISHMENTS ACCOUNTABLENESS ACHONDROPLASIAS
AEROELASTICIANS AGRANULOCYTOSES AGRANULOCYTOSIS ALCOHOLISATIONS
ALLEGORICALNESS ANCYLOSTOMIASES ANCYLOSTOMIASIS ANTIALCOHOLISMS
ANTICAPITALISMS ANTICAPITALISTS ANTICONVULSANTS ANTICONVULSIVES
ANTINEOPLASTICS ANTINUCLEARISTS ANTIPHLOGISTICS ANTIRADICALISMS
ANTISOCIALITIES ANTISYPHILITICS APOCALYPTICISMS ASCLEPIADACEOUS
ASSOCIABILITIES ASTROPHYSICALLY ATHEROSCLEROSES ATHEROSCLEROSIS
BACTERIOLOGISTS BIDIALECTALISMS BLOCKHEADEDNESS CAPITALISATIONS
CARAMELISATIONS CATEGORICALNESS CAUSELESSNESSES CEASELESSNESSES
CENSURABILITIES CENTRALISATIONS CENTRICALNESSES CENTRIFUGALISES
CENTRIPETALISMS CHALCOGRAPHISTS CHANCELLORSHIPS CHANGEFULNESSES
CHANNELISATIONS CHAPTALISATIONS CHLORITISATIONS CHOLESTYRAMINES
CHOLINESTERASES CHROMATOLOGISTS CIRCUMSTANTIALS CLAMOROUSNESSES
CLANDESTINENESS CLANDESTINITIES CLASSICALNESSES CLASSIFICATIONS
CLASSLESSNESSES CLAUSTROPHILIAS CLAUSTROPHOBIAS CLEARHEADEDNESS
CLEAVABLENESSES CLEISTOGAMOUSLY COESSENTIALNESS COLDHEARTEDNESS
COLONISATIONIST COLORABLENESSES COLORFASTNESSES COMFORTABLENESS
COMMENDABLENESS COMMONPLACENESS COMPASSIONATELY COMPLIANTNESSES
COMPLICATEDNESS COMRADELINESSES CONCEIVABLENESS CONCEPTUALISERS
CONFESSIONALISM CONFESSIONALIST CONFORMABLENESS CONFUSABILITIES
CONGEALABLENESS CONGENIALNESSES CONGRESSIONALLY CONQUERABLENESS
CONSENTANEOUSLY CONSIMILARITIES CONSTITUTIONALS CONSULTANTSHIPS
CONTESTABLENESS CONTINENTALISMS CONTINENTALISTS CONTINUALNESSES
CONVALESCENCIES CONVERSABLENESS CONVULSIONARIES CORPOREALNESSES
CORPUSCULARIANS CORRELATIVENESS COSMOPOLITANISM COUNTERASSAULTS
CRAPULOUSNESSES CRESTFALLENNESS CRUCIVERBALISMS CRUCIVERBALISTS
CRYSTALISATIONS CRYSTALIZATIONS CRYSTALLINITIES CRYSTALLISATION
CYCLOOXYGENASES CYLINDRICALNESS DECASUALISATION DECIMALISATIONS
DECOLONISATIONS DECOLORISATIONS DELOCALISATIONS DESACRALISATION
DESPICABILITIES DIALECTOLOGISTS DICTATORIALNESS DISACKNOWLEDGES
DISAPPLICATIONS DISARTICULATORS DISCIPLINARIANS DISCIPLINARIUMS
DISCOLOURATIONS DISCOMBOBULATES DISCONSOLATIONS DISGRACEFULNESS
DISINCLINATIONS DISSOCIABLENESS DODECASYLLABLES DOLICHOSAURUSES
DYSLOGISTICALLY ECCLESIASTICISM ECCLESIOLATRIES ECLAIRCISSEMENT
EDUCATIONALISTS EFFECTUALNESSES ELECTROANALYSES ELECTROANALYSIS
ELECTRODIALYSES ELECTRODIALYSIS EMPIRICALNESSES EMULSIFICATIONS
ENCYCLOPAEDISMS ENCYCLOPAEDISTS EPISCOPALIANISM EQUIVOCALNESSES
ESEMPLASTICALLY EVANGELICALISMS EVANGELICALNESS EXCEPTIONALISMS
EXCEPTIONALISTS EXCEPTIONALNESS EXCITABLENESSES EXCLAUSTRATIONS
EXCUSABLENESSES EXECRABLENESSES FANATICALNESSES FANTASTICALNESS
FETISHISTICALLY FORENSICALITIES GLOSSOGRAPHICAL GRACELESSNESSES
GRAMMATICALNESS GRAPHICALNESSES HEPATICOLOGISTS HOMOSOCIALITIES
HYDROCEPHALUSES IDENTICALNESSES IDIOMATICALNESS IDIOTICALNESSES
ILLOGICALNESSES IMMEDICABLENESS IMPLICATIVENESS IMPRACTICALNESS
INACCESSIBILITY INCAPABLENESSES INCREMENTALISMS INCREMENTALISTS
INCURABLENESSES INEFFECTUALNESS INEXCUSABLENESS INSCRIBABLENESS
INSCRUTABLENESS INSOCIABILITIES INTERSCHOLASTIC INTERSECTIONALS
INTRACTABLENESS INTRINSICALNESS IRASCIBLENESSES IRREVOCABLENESS
ISMATICALNESSES KAFFEEKLATSCHES LACTIFEROUSNESS LARYNGOSCOPISTS
LEUCAEMOGENESES LEUCAEMOGENESIS LEXICALISATIONS LEXICOGRAPHISTS
LICENTIATESHIPS LISSENCEPHALIES LISSENCEPHALOUS LUCRATIVENESSES
MALICIOUSNESSES MASCULINENESSES MASCULINISATION MASOCHISTICALLY
MATCHLESSNESSES MATRIARCHALISMS MEDICALISATIONS MERCURIALNESSES
MESATICEPHALIES MESATICEPHALOUS METALINGUISTICS MICROPULSATIONS
MICROSATELLITES MISAPPLICATIONS MISCALCULATIONS MISCELLANARIANS
MISCELLANEOUSLY MISCORRELATIONS MISVOCALISATION MULTIRACIALISMS
MUSCULOSKELETAL MUSICALISATIONS MUSICALIZATIONS NEOCOLONIALISMS
NEOCOLONIALISTS NONCONSENSUALLY NONELASTICITIES NONSENSICALNESS
NONSPECTACULARS NUCLEARISATIONS OCCASIONALITIES OMOPLATOSCOPIES
OPHTHALMOSCOPES ORACULOUSNESSES OSCILLOGRAPHIES OVERCAPITALISES
OVERCENTRALISES OVERCLASSIFYING OVERSPECIALISED OVERSPECIALISES
OVERSPECIALIZES PALEOECOLOGISTS PARADOXICALNESS PARALINGUISTICS
PARASITICALNESS PARTICULARISERS PASSIFLORACEOUS PATRIARCHALISMS
PEACEABLENESSES PEACELESSNESSES PENTADACTYLISMS PERISSODACTYLES
PERISSODACTYLIC PERISSOSYLLABIC PERSPICACIOUSLY PESSIMISTICALLY
PHALLOCENTRISMS PHARISAICALNESS PHARMACOLOGISTS PHARMACOPOLISTS
PHYLLOSILICATES PICTORIALNESSES PINEALECTOMISES PLACELESSNESSES
PLASTICISATIONS PLASTICIZATIONS POLITICISATIONS POLYCHROMATISMS
POLYSACCHARIDES POLYSACCHAROSES POLYSYLLABICISM POSTADOLESCENCE
POSTADOLESCENTS POSTAPOCALYPSES POSTCONSONANTAL PRACTICABLENESS
PRACTICALNESSES PRAGMATICALNESS PREADOLESCENCES PREDICTABLENESS
PREJUDICIALNESS PRINCIPALNESSES PROCELEUSMATICS PROCESSIONALIST
PROSAICALNESSES PSYCHOANALYSERS PSYCHOANALYSING PSYCHOANALYZERS
PSYCHOCHEMICALS PSYCHOSEXUALITY PURITANICALNESS QUADRISYLLABICS
RADICALISATIONS RECANALISATIONS RECOLONISATIONS RECOVERABLENESS
RECRYSTALLISING REPROACHFULNESS RESECTABILITIES RESOCIALISATION
RESPECTABILISED RESPECTABILISES RESPECTABILIZES RESPECTABLENESS
REVOCABLENESSES SACERDOTALISING SACRAMENTALISMS SACRAMENTALISTS
SACRAMENTALNESS SALACIOUSNESSES SALPINGECTOMIES SANCTIMONIOUSLY
SANGUINOLENCIES SANSCULOTTERIES SATANICALNESSES SATIRICALNESSES
SCANDALISATIONS SCANDALIZATIONS SCAPHOCEPHALICS SCAPHOCEPHALIES
SCAPHOCEPHALISM SCAPHOCEPHALOUS SCATHEFULNESSES SCEUOPHYLACIUMS
SCHILLERISATION SCHOLARLINESSES SCHOOLMASTERING SCHOOLMASTERISH
SCHOOLTEACHINGS SCINTILLASCOPES SCLERODERMATOUS SCLEROTHERAPIES
SCLEROTISATIONS SCLEROTIZATIONS SCRATCHBUILDERS SEARCHABILITIES
SECULARISATIONS SECULARIZATIONS SEISMOGRAPHICAL SEISMOLOGICALLY
SEMICENTENNIALS SEMICOLONIALISM SEMICRYSTALLINE SEMITRANSLUCENT
SEROPREVALENCES SERVICEABLENESS SILICIFICATIONS SIMPLIFICATIONS
SKEPTICALNESSES SKETCHABILITIES SOCIALISTICALLY SOCIOHISTORICAL
SOLIDIFICATIONS SOLIPSISTICALLY SOPHISTICATEDLY SPECIALISATIONS
SPECIALIZATIONS SPECTROSCOPICAL SPECULATIVENESS SPERMATOBLASTIC
SPHAEROCRYSTALS SPHERICALNESSES SPIRONOLACTONES SPLANCHNOLOGIES
STAPHYLOPLASTIC STEEPLECHASINGS STEGOCEPHALIANS STRAITLACEDNESS
STRATICULATIONS STRATOSPHERICAL STRATOVOLCANOES STREPTOBACILLUS
STRUCTURALISING STULTIFICATIONS SUBCIVILISATION SUBSPECIALISING
SUBSPECIALITIES SUBSPECIALIZING SUBSPECIFICALLY SUBVOCALISATION
SULPHACETAMIDES SUPERFICIALISED SUPERFICIALISES SUPERFICIALIZES
SUPERFICIALNESS SUPERPLASTICITY SUPERSPECIALIST SUPERSPECTACLES
SUPERSTRUCTURAL SUSPERCOLLATING SYLLOGISTICALLY SYMBOLISTICALLY
SYMMETRICALNESS SYNCHRONISTICAL SYNERGISTICALLY TEACHABLENESSES
TECHNICALNESSES TELANGIECTASIAS THALASSOCRACIES THALASSOGRAPHIC
THEOSOPHISTICAL THORACOPLASTIES TOUCHABLENESSES TRACEABLENESSES
TRACKLESSNESSES TRACTABLENESSES TRANSCENDENTALS TRANSHISTORICAL
TRANSLUCIDITIES ULTRAPRECISIONS ULTRASTRUCTURES UNCANONICALNESS
UNCLEANLINESSES UNCLIMBABLENESS UNEQUIVOCALNESS UNMUSICALNESSES
UNPEACEABLENESS UNPRACTICALNESS UNSOCIABILITIES UNTACTFULNESSES
UNTEACHABLENESS UNTRACTABLENESS VASCULARISATION VERTICILLASTERS
VISCOELASTICITY VISCOSIMETRICAL WATERCOLOURISTS WELTANSCHAUUNGS
WHIMSICALNESSES