There are 419 fourteen-letter words containing A, I, M, N and U, https://www.bestwordlist.com/c/a/5/14letterwordswithaimnu.htm
ABSTEMIOUSNESS ACCUSTOMATIONS ACTINOMORPHOUS ACTINOMYCETOUS ACTINOURANIUMS
ADIATHERMANOUS ADMINICULATING ALPHANUMERICAL AMATEURISHNESS AMINOACIDURIAS
AMPHIBIOUSNESS ANGIOSTOMATOUS ANTEPENULTIMAS ANTHROPOPHUISM ANTICOMMUNISMS
ANTICOMMUNISTS ANTIHOMOSEXUAL ANTIHUMANISTIC ANTIQUARIANISM ANTIRHEUMATICS
ANTIRITUALISMS ARGUMENTATIONS ARMAMENTARIUMS AUDIOMETRICIAN AUGMENTATIVELY
AUTOCHTHONISMS AUTOIMMUNITIES AUTOMATISATION AUTOMATIZATION BALSAMINACEOUS
BILDUNGSROMANS BITUMINISATION BITUMINIZATION CALAMITOUSNESS CATECHUMENICAL
CATECHUMENISMS CATECHUMENSHIP CERULOPLASMINS CHONDROCRANIUM CHURCHMANLIEST
CHURCHMANSHIPS CIRCUMAMBIENCE CIRCUMAMBIENCY CIRCUMFORANEAN CIRCUMGYRATING
CIRCUMGYRATION CIRCUMNAVIGATE CIRCUMNUTATING CIRCUMNUTATION CIRCUMNUTATORY
CIRCUMROTATING CIRCUMSTANCING CIRCUMSTANTIAL COMMENSURATION COMMUNAUTAIRES
COMMUNICATIONS COMMUNISATIONS COMMUNITARIANS COMMUNIZATIONS CONCEPTUALISMS
CONNUMERATIONS CONSERVATORIUM CONTUMACIOUSLY COUNTERCLAIMED COUNTERMANDING
CUMULATIVENESS CUSTOMISATIONS CUSTOMIZATIONS CYANOBACTERIUM DECAMETHONIUMS
DEHUMANISATION DEHUMANIZATION DENUMERABILITY DIAMANTIFEROUS DIAMONDIFEROUS
DISACCUSTOMING DISAMBIGUATING DISAMBIGUATION DISCIPLINARIUM DISCOURAGEMENT
DISENCUMBRANCE DISFEATUREMENT DISILLUMINATED DISILLUMINATES DISSIMULATIONS
DOCUMENTALISTS DOCUMENTARIANS DOCUMENTARISED DOCUMENTARISES DOCUMENTARISTS
DOCUMENTARIZED DOCUMENTARIZES DOCUMENTATIONS DUNDERHEADISMS ECUMENICALISMS
ELEUTHEROMANIA EMULSIFICATION EQUESTRIANISMS EUDEMONISTICAL EVANGELIARIUMS
EXCOMMUNICABLE EXCOMMUNICATED EXCOMMUNICATES EXCOMMUNICATOR FLUNITRAZEPAMS
FORAMINIFEROUS FRUITARIANISMS FUNAMBULATIONS FUNCTIONALISMS FUNDAMENTALISM
FUNDAMENTALIST FUNDAMENTALITY GEWURZTRAMINER HAEMAGGLUTININ HAEMODILUTIONS
HARMONIOUSNESS HAUSSMANNISING HAUSSMANNIZING HEMAGGLUTINATE HEMAGGLUTININS
HEMOGLOBINURIA HEXAMETHONIUMS HOUGHMAGANDIES HUMANISTICALLY HUMBLEBRAGGING
HUMIDIFICATION HYDROPNEUMATIC HYPERMASCULINE HYPERURBANISMS ILLUMINATINGLY
ILLUMINATIONAL IMMACULATENESS IMMATURENESSES IMMUNOASSAYIST IMMUNOCHEMICAL
IMMUNOREACTION IMMUNOREACTIVE IMPERTURBATION IMPOSTHUMATING IMPOSTHUMATION
IMPOSTUMATIONS INCOMMENSURATE INCOMMUNICABLE INCOMMUNICABLY INDIVIDUALISMS
INDUSTRIALISMS INFAMOUSNESSES INHARMONIOUSLY INNUMERABILITY INSTRUMENTALLY
INSURMOUNTABLE INSURMOUNTABLY INTERAMBULACRA INTERMENSTRUAL INTERMOLECULAR
INTERSEXUALISM INTRAMEDULLARY INTRAMERCURIAL INTRAMOLECULAR INTRANSMUTABLE
INTUITIONALISM LIQUIDATIONISM MACHINEGUNNING MACROEVOLUTION MACROGLOBULINS
MACROMUTATIONS MACRONUTRIENTS MAGNILOQUENCES MAGNILOQUENTLY MALFUNCTIONING
MANIPULABILITY MANIPULATIVELY MANRIKIGUSARIS MANUFACTURINGS MATRICULATIONS
MEANINGFULNESS MEGALOSAURIANS MEGASPORANGIUM MENDACIOUSNESS MERCAPTOPURINE
MERCURIALISING MERCURIALIZING METACOMPUTINGS METALINGUISTIC MICROMINIATURE
MICROPULSATION MINICALCULATOR MIRACULOUSNESS MISADJUSTMENTS MISADVENTURERS
MISADVENTUROUS MISASSUMPTIONS MISATTRIBUTING MISATTRIBUTION MISCALCULATING
MISCALCULATION MISCATALOGUING MISCOMPUTATION MISEVALUATIONS MISGOVERNAUNCE
MISMEASUREMENT MISPERSUASIONS MISPUNCTUATING MISPUNCTUATION MISUNDERSTANDS
MISUTILISATION MISUTILIZATION MOCKUMENTARIES MONOLINGUALISM MONUMENTALISED
MONUMENTALISES MONUMENTALIZED MONUMENTALIZES MORDACIOUSNESS MOUNTAINBOARDS
MOUNTAINEERING MOUNTEBANKINGS MOUNTEBANKISMS MOUSETRAPPINGS MUCILAGINOUSLY
MULLIGATAWNIES MULTICANDIDATE MULTIFILAMENTS MULTILINGUALLY MULTILOCATIONS
MULTINATIONALS MULTINUCLEATED MULTINUCLEOLAR MULTIPLATINUMS MULTIPLICATION
MULTIPOTENTIAL MULTITERMINALS MULTITHREADING MULTIVALENCIES MUMMIFICATIONS
MUNDIFICATIONS MUNDIFICATIVES MUNICIPALISING MUNICIPALITIES MUNICIPALIZING
MUSICALISATION MUSICALIZATION MUTAGENICITIES MUTUALISATIONS MUTUALIZATIONS
NEURAMINIDASES NEUROANATOMIES NEUROANATOMIST NEUROCHEMICALS NEUROFIBROMATA
NEUROMARKETING NITROBACTERIUM NOCTAMBULATION NONCOMMUNICANT NONCOMMUTATIVE
NONFILAMENTOUS NUMERABILITIES NUMISMATICALLY OMBUDSMANSHIPS OSMOREGULATION
OUTMANEUVERING OUTMANIPULATED OUTMANIPULATES OUTMANOEUVRING OVERENTHUSIASM
PARAJOURNALISM PARSIMONIOUSLY PERAMBULATIONS PERIMENOPAUSAL PERIMENOPAUSES
PLATINIRIDIUMS PLOUGHMANSHIPS PNEUMATICITIES PNEUMATOLOGIES PNEUMATOLOGIST
PNEUMOBACILLUS PNEUMODYNAMICS PNEUMOGASTRICS POCOCURANTEISM POCOCURANTISMS
POLEMONIACEOUS POSTAMPUTATION PREFORMULATING PREMANDIBULARS PRONUNCIAMENTO
PROTOACTINIUMS PRUDENTIALISMS QUADRIGEMINATE QUADRIGEMINOUS QUALMISHNESSES
QUARTODECIMANS QUATTROCENTISM QUINQUAGESIMAL RADIOSTRONTIUM RAMBUNCTIOUSLY
RECOMPUTATIONS REFORMULATIONS REHUMANIZATION REMUNERABILITY REMUNERATIVELY
REPUBLICANISMS RESTIMULATIONS SANSCULOTTISMS SCAPULIMANCIES SCAPULOMANCIES
SEMIAUTONOMOUS SIMULTANEITIES SIMULTANEOUSES SIMULTANEOUSLY SOMNAMBULATING
SOMNAMBULATION SOMNAMBULISTIC SPERMATOGONIUM SQUANDERMANIAS SUBMANDIBULARS
SUBMETACENTRIC SUBMINIATURISE SUBMINIATURIZE SUBNORMALITIES SUBSTANTIALISM
SUFFUMIGATIONS SULFADIMIDINES SULFAMETHAZINE SULFANILAMIDES SULPHANILAMIDE
SUMMARISATIONS SUMMARIZATIONS SUMMERSAULTING SUPERCRIMINALS SUPERDOMINANTS
SUPERHUMANISED SUPERHUMANISES SUPERHUMANIZED SUPERHUMANIZES SUPERIMPORTANT
SUPERMASCULINE SUPERMILITANTS SUPERNORMALITY SUPERORGANISMS SUPRALIMINALLY
TAUTOCHRONISMS TELEJOURNALISM THAUMATOGENIES TRANSEXUALISMS TRANSMUTATIONS
TRANSSEXUALISM TRAUMATISATION TRAUMATIZATION TRILINGUALISMS TROUBLEMAKINGS
TURBOMACHINERY ULTIMATENESSES ULTRAMASCULINE ULTRAMILITANTS ULTRAMINIATURE
ULTRAMODERNISM ULTRAMODERNIST ULTRAMONTANISM ULTRAMONTANIST ULTRAROMANTICS
UNACADEMICALLY UNACCLIMATISED UNACCLIMATIZED UNACCOMPLISHED UNAMBIVALENTLY
UNAMIABILITIES UNASSUMINGNESS UNATHLETICISMS UNCOMMUNICABLE UNCOMMUNICATED
UNCONTAMINATED UNDEREMPHASISE UNDEREMPHASIZE UNDERESTIMATED UNDERESTIMATES
UNDETERMINABLE UNDETERMINABLY UNDIMINISHABLE UNDOGMATICALLY UNDOMESTICATED
UNDOMESTICATES UNDRAMATICALLY UNEMBARRASSING UNEMPHATICALLY UNICAMERALISMS
UNICAMERALISTS UNIDIMENSIONAL UNIFORMITARIAN UNILATERALISMS UNILINGUALISMS
UNILLUMINATING UNINTIMIDATING UNMAINTAINABLE UNMALLEABILITY UNMANNERLINESS
UNMARRIAGEABLE UNMATERIALISED UNMATERIALIZED UNMATHEMATICAL UNMATRICULATED
UNMENTIONABLES UNMETAPHORICAL UNMETAPHYSICAL UNPREMEDITABLE UNPREMEDITATED
UNREMUNERATIVE UNRHYTHMICALLY UNROMANTICALLY UNROMANTICISED UNROMANTICIZED
UNSECTARIANISM UNSYMPATHISING UNSYMPATHIZING UNSYSTEMATICAL UNSYSTEMATISED
UNSYSTEMATIZED UTILITARIANISM VERMICULATIONS VERNACULARISMS