The List
There are 458 7 letter words with M as the last letter. The highest scoring is JUJUISM at 23 points in Scrabble. 262 carry three or more vowels, which makes them useful for dumping a vowel-clogged rack.
ABLEISMACCLAIMACIFORMACRONYMAGENDUMALIFORMALLONYMALODIUMALUMIUMALYSSUMAMALGAMAMENTUMAMORISMANAGRAMANIMISMANTIJAMANTONYMAPOTHEMARCANUMASTEISMATAVISMATHEISMATOMISMAUSFORMAUTONYMAVIFORMBAALISMBABUDOMBABUISMBACULUMBAGWORMBALLIUMBAPTISMBARDISMBARROOMBECHARMBEDROOMBEGLOOMBEMADAMBERSEEMBESTORMBESWARMBIOFILMBIOHERMBIPRISMBLELLUMBLIKSEMBLOSSOMBLUEGUMBOGYISMBOHRIUMBOREDOMBOSSDOMBOSSISMBOXROOMBRECHAMBROMISMBRUTISMBRUXISMBUCKRAMBUCKSOMBUDWORMCACONYMCADMIUMCAESIUMCALCIUMCAMBISMCAMBIUMCATWORMCENTRUMCHARISMCHEFDOMCHEMISMCHETRUMCHILLUMCHORISMCHRISOMCLADISMCLONISMCOCOYAMCONFIRMCONFORMCOPYISMCOSMISMCRANIUMCRETISMCRISSUMCRUMBUMCULTISMCUTWORMCZARDOMCZARISMDADAISMDAYANIMDAYROOMDECLAIMDECORUMDEIFORMDEMONYMDIADROMDIAGRAMDIASTEMDIFFORMDIGICAMDIORISMDISFORMDISHELMDIVISIMDODOISMDOGEDOMDOLLDOMDONNISMDUALISMDUBNIUMDUKEDOMEARDRUMEARLDOMEARWORMECHOISMEELWORMEGOTISMELITISMELOGIUMELUVIUMELYTRUMEMBLOOMEMBOSOMENCHARMENGLOOMENRHEUMENTRISMENVENOMEPIBLEMEPICISMEPIDERMEPIGRAMEPITHEMERATHEMERODIUMERRATUMETACISMETATISMEXCLAIMEXODERMEXOTISMEXUVIUMEYEBEAMFADDISMFALSISMFANTASMFASCISMFATTISMFAUVISMFERMIUMFIDEISMFIEFDOMFILMDOMFINDRAMFIREARMFLOTSAMFOGYDOMFOGYISMFOODISMFOREARMFRAENUMFREEDOMFRUSTUMFULCRUMGALLIUMGEEKDOMGINGHAMGOPURAMGRANDAMGRANNAMGRANNOMGRASSUMGROGRAMGUNROOMGURUDOMGURUISMHADARIMHAFNIUMHAHNIUMHALIDOMHANDISMHASSIUMHAZANIMHEIRDOMHEROISMHEURISMHOBODOMHOBOISMHOLESOMHOLMIUMHOLYDAMHOMONYMHOODLUMHUMDRUMHUMMAUMHYPONYMIDEATUMIDOLISMIMAGISMIMBOSOMINFIMUMINTERIMIRIDIUMISCHIUMISOFORMISOGRAMITACISMJARLDOMJEJUNUMJIBBOOMJUGULUMJUJUISMKARAISMKINGDOMKOHANIMLABARUMLADANUMLADDISMLADYISMLAICISMLECHAIMLEFTISMLEGGISMLEGITIMLEGROOMLEHAYIMLIONISMLITHIUMLOBWORMLOCKRAMLOCOISMLOOKISMLUGWORMLUSTRUMMACADAMMAIDISMMANTRAMMASHLAMMASHLIMMASHLUMMAXIMUMMERONYMMESCLUMMETONYMMICROHMMIDTERMMILLDAMMINICAMMINICOMMINIMUMMISDEEMMISFORMMISSEEMMISTERMMOBBISMMODICUMMOHALIMMOHELIMMONONYMMUDROOMMUONIUMMYALISMMYOGRAMMYTHISMNARCISMNATRIUMNEURISMNIOBIUMNONFARMNOSTRUMNOTAEUMOBELISMODYLISMOESTRUMOFFSCUMOGREISMOMENTUMONANISMOOSPERMOPOSSUMOPTIMUMORALISMORARIUMORGANUMORPHISMOSCULUMOUTBEAMOUTSWAMOUTSWIMOUTSWUMOVERARMOVIFORMOXONIUMPABULUMPALLIUMPANGRAMPANICUMPANTOUMPAPADAMPAPADOMPAPADUMPARANYMPARONYMPEONISMPERFORMPHAEISMPHANTOMPHELLEMPHOBISMPHOTISMPIANISMPIETISMPILGRIMPINETUMPINWORMPLAGIUMPLENISMPLUMBUMPOLYGAMPOMATUMPOPADUMPOPEDOMPREBOOMPREDOOMPREFORMPREMIUMPRETERMPRETRIMPREWARMPROBLEMPROGRAMPROTIUMPUNCTUMPYTHIUMQUANTUMQUONDAMRAGWORMRAMSTAMRANKISMRASTRUMREALISMREBLOOMRECLAIMREDREAMREGROOMRELATUMREQUIEMRHABDOMRHENIUMRHODIUMROSTRUMSANCTUMSARCASMSCHTOOMSEAWORMSECULUMSEDARIMSELFDOMSELFISMSENSISMSERFDOMSHAHDOMSHITTIMSHIURIMSIDEARMSISTRUMSIZEISMSKELLUMSKOOKUMSLUMGUMSLUMISMSMEDDUMSOLANUMSOLIDUMSOPHISMSORGHUMSPODIUMSTADIUMSTANNUMSTARDOMSTATISMSTERNUMSTEWBUMSTIBIUMSTICKUMSTOMIUMSTRATUMSUBATOMSUBITEMSUNBEAMSUNROOMSYMPTOMSYNONYMSYNTAGMTACHISMTACTISMTAEDIUMTANGRAMTANTRUMTAPETUMTAPROOMTEAROOMTELECOMTERAOHMTERBIUMTERTIUMTETOTUMTHEOREMTHORIUMTHULIUMTONEARMTOPONYMTOURISMTOYLSOMTRANGAMTRANKUMTRANSOMTRIDUUMTRIFORMTRIGRAMTRINKUMTRIONYMTRITIUMTRIVIUMTROPISMTSARDOMTSARISMTYCHISMTZARDOMTZARISMULPANIMUNBOSOMUNCHARMUNIFORMURANISMURANIUMUREDIUMUTOPISMVITREUMWAXWORMWEBWORMWHANGAMWHOLISMWIFEDOMWILLIAMWOLFRAMXANTHAMYARDARMYOBBISMYTTRIUMZANYISMZOARIUMZOECIUMZOEFORM