before vowels somat-, word-forming element meaning "the body of an organism," from combining form of Greek sōma (genitive sōmatos) "the body, a human body dead or living, body as opposed to spirit; material substance; mass; a person, human being; the whole body or mass of anything," a word of uncertain origin. Perhaps originally "compactness, swelling," and from PIE root *teue- "to swell."
word-forming element of Greek origin meaning "divination by means of," from Old French -mancie, from Late Latin -mantia, from Greek manteia "oracle, divination," from mantis "one who divines, a seer, prophet; one touched by divine madness," from mainesthai "be inspired," which is related to menos "passion, spirit" (from PIE *mnyo-, suffixed form of root *men- (1) "to think," with derivatives referring to qualities and states of mind or thought). Compare mania.
word-forming element used in making adjectives from nouns or adjectives (and sometimes verbs) and meaning "tending to; causing; to a considerable degree," from Old English -sum, identical with some, from PIE root *sem- (1) "one; as one, together with." Cognate with Old Frisian -sum, German -sam, Old Norse -samr; also related to same. "It usually indicates the possession of a considerable degree of the quality named: as mettlesome, full of mettle or spirit; gladsome, very glad or joyous" [Century Dictionary]. For the -some used with numbers (twosome, foursome, etc.), see -some (2).