macabre :: gruesome; grisly
Machiavellian :: crafty; double-dealing
magnanimous :: generous
magniloquent :: boastful; pompous
malevolent :: wishing evil
malicious :: dictated by hatred or spite
malignant :: having an evil influence; virulent
malleable :: capable of being shaped by pounding
mammoth :: gigantic
mandatory :: obligatory
maniacal :: raving mad
manifest :: understandable; clear
marital :: pertaining to marriage
maritime :: bordering on the sea; nautical
martial :: warlike
maternal :: motherly
maudlin :: effusively sentimental
mauve :: pale purple
meddlesome :: interfering
mediocre :: ordinary; commonplace
mellifluous :: flowing smoothly; smooth
mendacious :: lying; false
menial :: suitable for servants; low
mercantile :: concerning trade
mercenary :: interested in money or gain
mercurial :: fickle; changing
meretricious :: flashy; tawdry
metallurgical :: pertaining to the art of removing metals from ores