There are 392 fifteen-letter words containing A, C, L, P and T, https://www.bestwordlist.com/c/a/5/15letterwordswithaclpt.htm
ACANTHOCEPHALAN ACCEPTABILITIES ACCOMPANIMENTAL ACCOMPLISHMENTS
ACHONDROPLASTIC ALLOTRIOMORPHIC AMPHITHEATRICAL ANISOTROPICALLY
ANTHROPOLOGICAL ANTICAPITALISMS ANTICAPITALISTS ANTINEOPLASTICS
ANTIPERISTALTIC ANTIPHLOGISTICS ANTIREPUBLICANS ANTISPECULATION
ANTISPECULATIVE ANTISYPHILITICS APOCALYPTICALLY APOCALYPTICISMS
APOLITICALITIES APPLICABILITIES APPROACHABILITY ASTROPHYSICALLY
ATMOSPHERICALLY AUTOGRAPHICALLY AUTOMORPHICALLY AUTOTROPHICALLY
CAPITALISATIONS CAPITALIZATIONS CENTRIPETALISMS CENTUPLICATIONS
CEPHALOCHORDATE CEPHALOTHORACES CEPHALOTHORACIC CEPHALOTHORAXES
CHALCOGRAPHISTS CHANNELOPATHIES CHAPTALISATIONS CHAPTALIZATIONS
CHARTOGRAPHICAL CHEMOTROPICALLY CLAUSTROPHILIAS CLAUSTROPHOBIAS
CLIMATOGRAPHIES COMPARABILITIES COMPARTMENTALLY COMPASSIONATELY
COMPATIBILITIES COMPLEMENTARIES COMPLEMENTARILY COMPLEMENTARITY
COMPLEMENTATION COMPLIANTNESSES COMPLICATEDNESS COMPLIMENTARILY
COMPOSITIONALLY COMPUTABILITIES COMPUTATIONALLY CONCEPTUALISERS
CONCEPTUALISING CONCEPTUALISTIC CONCEPTUALITIES CONCEPTUALIZERS
CONCEPTUALIZING CONDUPLICATIONS CONSULTANTSHIPS CONTEMPLATIVELY
CONTRAPROPELLER CONTRAPUNTALIST COSMOPOLITANISM COUNTEREXAMPLES
COUNTERPLANNING COUNTERPLEADING COUNTERPROPOSAL CRYPTANALYTICAL
CRYPTOGRAPHICAL CRYSTALLOGRAPHY CYCLOPENTADIENE CYCLOPENTOLATES
CYTOPATHOLOGIES CYTOPATHOLOGIST CYTOPLASMICALLY DACTYLOGRAPHERS
DACTYLOGRAPHIES DECIPHERABILITY DECOMPOSABILITY DEPHLOGISTICATE
DERMATOGLYPHICS DESPICABILITIES DIASTROPHICALLY DISAPPLICATIONS
DUPLICABILITIES ELECTROGRAPHIES ELECTROMYOGRAPH ELECTROPLATINGS
ELECTROPORATION ENCEPHALITOGENS ENCEPHALOPATHIC ENCEPHALOTOMIES
ENCYCLOPAEDISTS EPISTEMOLOGICAL ESEMPLASTICALLY EUPHEMISTICALLY
EXCEPTIONALISMS EXCEPTIONALISTS EXCEPTIONALNESS EXEMPLIFICATION
EXEMPLIFICATIVE GALACTOPOIETICS GEOSTROPHICALLY GLYPTOGRAPHICAL
HELIOTROPICALLY HEPATICOLOGICAL HEPATICOLOGISTS HETEROGRAPHICAL
HISTOCOMPATIBLE HISTOPATHOLOGIC HOMEOPATHICALLY HOMOPLASTICALLY
HYDROPATHICALLY HYDROTROPICALLY HYPERCATABOLISM HYPERCATALECTIC
HYPERCRITICALLY HYPERFUNCTIONAL HYPERMETROPICAL HYPOCRYSTALLINE
HYPSOMETRICALLY IMPECCABILITIES IMPLACABILITIES IMPLICATIVENESS
IMPRACTICALNESS INAPPLICABILITY INCOMPARABILITY INCOMPATIBILITY
INCOMPUTABILITY INCULPABILITIES INEXPLICABILITY INTERPERCEPTUAL
INTERPROVINCIAL INTROSPECTIONAL ISOPERIMETRICAL LAPIDIFICATIONS
LARYNGOSCOPISTS LEUCOCYTOPENIAS LEUKOCYTOPENIAS LEXICOGRAPHISTS
LICENTIATESHIPS LOPHOBRANCHIATE LYMPHOCYTOPENIA LYMPHOSARCOMATA
MACROPRUDENTIAL MALACOPTERYGIAN MALPRACTITIONER MESATICEPHALIES
MESATICEPHALOUS METAMORPHICALLY METOCLOPRAMIDES MICROPULSATIONS
MISAPPLICATIONS MULTIPLICATIONS NEUROPATHICALLY NEUROPATHOLOGIC
NEUROPLASTICITY NONENCAPSULATED NONIMPLICATIONS NONMETAPHORICAL
NONOCCUPATIONAL NONSPECTACULARS NUCLEOPLASMATIC OMOPLATOSCOPIES
OPHTHALMOSCOPES OPHTHALMOSCOPIC ORTHOPAEDICALLY OSTEOPATHICALLY
OVERAPPLICATION OVERCAPITALISED OVERCAPITALISES OVERCAPITALIZED
OVERCAPITALIZES OVERCOMPLICATED OVERCOMPLICATES OVERSPECULATING
OVERSPECULATION PALAEOANTHROPIC PALAEOBOTANICAL PALAEOECOLOGIST
PALEOECOLOGISTS PALEONTOLOGICAL PANTHEISTICALLY PANTISOCRATICAL
PARAGENETICALLY PARAHELIOTROPIC PARALINGUISTICS PARALLACTICALLY
PARASITICALNESS PARASITOLOGICAL PARENTHETICALLY PARTICIPATIONAL
PARTICULARISERS PARTICULARISING PARTICULARISTIC PARTICULARITIES
PARTICULARIZERS PARTICULARIZING PATRIARCHALISMS PATRIFOCALITIES
PENTADACTYLISMS PERFECTIBILIANS PERIODONTICALLY PERIPATETICALLY
PERISSODACTYLES PERISSODACTYLIC PERISTALTICALLY PESSIMISTICALLY
PETROCHEMICALLY PHALLOCENTRISMS PHARMACEUTICALS PHARMACOLOGISTS
PHARMACOPOLISTS PHENOMENALISTIC PHILANTHROPICAL PHLOGISTICATING
PHOTOBIOLOGICAL PHOTOCHEMICALLY PHOTODUPLICATED PHOTODUPLICATES
PHOTOELASTICITY PHOTOELECTRICAL PHOTOGEOLOGICAL PHOTOMECHANICAL
PHOTOMETRICALLY PHOTOTACTICALLY PHOTOTROPICALLY PHTHALOCYANINES
PHYLLOSILICATES PHYTOCHEMICALLY PHYTOPLANKTONIC PICTORIALNESSES
PIEZOMETRICALLY PINEALECTOMISED PINEALECTOMISES PINEALECTOMIZED
PINEALECTOMIZES PINOCYTOTICALLY PISCICULTURALLY PLAINCLOTHESMAN
PLAINCLOTHESMEN PLANIMETRICALLY PLANOMETRICALLY PLANTAGINACEOUS
PLASMOLYTICALLY PLASTICISATIONS PLASTICIZATIONS PLATINOCYANIDES
PLATYHELMINTHIC PLURALISTICALLY PLUTOCRATICALLY PNEUMATOLOGICAL
POLITICISATIONS POLITICIZATIONS POLYCARBOXYLATE POLYCHLORINATED
POLYCHROMATISMS POLYCRYSTALLINE POLYGENETICALLY POLYSYNTHETICAL
PONTIFICALITIES POSTADOLESCENCE POSTADOLESCENTS POSTAPOCALYPSES
POSTAPOCALYPTIC POSTCONSONANTAL POSTINOCULATION PRACTICABLENESS
PRACTICALNESSES PRAGMATICALNESS PREAGRICULTURAL PRECANCELLATION
PRECIPITABILITY PREDICABILITIES PREDICTABLENESS PREHISTORICALLY
PREPUBLICATIONS PRESYNAPTICALLY PROBLEMATICALLY PROCELEUSMATICS
PROCESSIONALIST PRONUNCIATIONAL PROTEOLYTICALLY PROTOZOOLOGICAL
PROVINCIALITIES PSEUDOCOELOMATE PSYCHIATRICALLY PSYCHOGENETICAL
PSYCHOPATHOLOGY PSYCHOSEXUALITY PSYCHROMETRICAL PULMOBRANCHIATE
PURITANICALNESS PYROTECHNICALLY QUADRUPLICATING QUADRUPLICATION
QUADRUPLICITIES QUINTUPLICATING QUINTUPLICATION RADICULOPATHIES
RADIOTELEPHONIC RECAPITULATIONS RECIPROCALITIES RECONCEPTUALISE
RECONCEPTUALIZE RECTIPETALITIES REDUPLICATIVELY REPLICABILITIES
RESPECTABILISED RESPECTABILISES RESPECTABILIZED RESPECTABILIZES
RESPECTABLENESS SALPINGECTOMIES SAPROPHYTICALLY SCINTILLASCOPES
SCLEROTHERAPIES SIMPLICIDENTATE SIMPLIFICATIONS SKEPTICALNESSES
SOLIPSISTICALLY SOPHISTICATEDLY SPECIALISATIONS SPECIALIZATIONS
SPECTROSCOPICAL SPECULATIVENESS SPERMATOBLASTIC SPHAEROCRYSTALS
SPIRONOLACTONES STAPHYLOPLASTIC STEEPLECHASINGS STEGOCEPHALIANS
STEREOGRAPHICAL STEREOTYPICALLY STRATIGRAPHICAL STRATOSPHERICAL
STREPTOBACILLUS SUBSPECIALITIES SULPHACETAMIDES SUPERPLASTICITY
SUPERSPECIALIST SUPERSPECTACLES SUPERSTRUCTURAL SUSPERCOLLATING
SYCOPHANTICALLY SYMPATHETICALLY SYMPTOMATICALLY SYMPTOMATOLOGIC
SYMPTOMOLOGICAL TELEGRAPHICALLY THALAMENCEPHALA THALASSOGRAPHIC
THEOSOPHISTICAL THERAPEUTICALLY THORACOPLASTIES TOPOGRAPHICALLY
TRANSCRIPTIONAL TRANSCRIPTIVELY TROPICALISATION TROPICALIZATION
TYPOGRAPHICALLY ULTRACREPIDATED ULTRACREPIDATES ULTRAMICROSCOPE
ULTRAMICROSCOPY ULTRAPRECISIONS UNACCEPTABILITY UNANTICIPATEDLY
UNAPOSTOLICALLY UNCOMPLAISANTLY UNCOMPLIMENTARY UNCOOPERATIVELY
UNCOPYRIGHTABLE UNDERCAPITALISE UNDERCAPITALIZE UNEXCEPTIONABLE
UNEXCEPTIONABLY UNEXCEPTIONALLY UNPATRIOTICALLY UNPRACTICALNESS
UNPUNCTUALITIES UNSPECTACULARLY XYLOTYPOGRAPHIC ZOOPHYTOLOGICAL