mellifluous,sweetly flowing
mendacious,false
mendacity,dishonesty 
mendicant,a beggar 
mercurial,quick/changeable in character/fleeting 
meretricious,attractive on the surface but of little value
mesmerize,hypnotize
meticulous,giving great attention to details
mettle,quality of endurance or courage
mettlesome,courageous/high-spirited
middling,fairly good but not very good
minatory,menacing/threatening
mince,pronounce or speak affectedly/euphemize/speak too carefully
misanthrope,person who hates mankind
mischievous,harmful/causing mischief
miser,person who loves wealth and spends little
misogynist,one who hates women/females 
missile,smth that is thrown or shot
mitigate,make less severe or painful
moderation,quality of being limited/not extreme
mollify,make calmer or quiter
molt,moult/lose hair/feathers before new growing
morbid,iseased/unhealthy (about ideas)
morose,ill-tempered/unsocial
mortuary,place where dead bodies are taken to be kept until burial
multifarious,varied/motley/greatly diversified 
mundane,worldly as opposed to spiritual/commonplace/everyday 
myriad,very great number
nadir,lowest/weakest point
nascent,coming into existance/emerging 
nebulous,cloud-like/hazy/vague/indistinct
negligent,taking too little care
neophyte,person who has been converted to a belief
nexus,a connection/tie or link 
nibble,show some inclination to accept (an offer)
nice,precise/sensitive to subtleness 
noisome,offensive/disgusting (smell)
nonchalant,not having interest
nonplussed,greatly surprised
nostrum,a quack remedy/an untested cure 
notion,nominal/token
noxious,harmful
nullify,make void and null
numb,without ability to feel or move
numbness,without ability to move a finger
obdurate,hardened and unrepenting/stubborn/inflexible 
obfuscate,to darken/make obscure/muddle 
oblivious,unaware/having no memory
obloquy,abusively detractive language/sharp criticism/vituperation
obsequious,too eager to obey or serve