venturesome (adj.)

early 15c., "to risk the loss" (of something), shortened form of aventure, itself a form of adventure. General sense of "to dare, to presume" is recorded from 1550s. Related: Ventured; venturing.

Nought venter nought have [Heywood, "Proverbs," 1546]

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]. It is also, disguised, the ending in buxom. For the -some used with numbers (twosome, foursome, etc.), see -some (2).