Cowardly
fainthearted, fearful, timorous, hesitant, pusillanimous, apprehensive, frightened, nervous, unnerved, tremulous, overcautious, spiritless, weak, weak-kneed, poor-spirited, shaky, feeble, daunted, browbeaten, cowed, intimidated, spineless, cowering, soft*, yellow*, scared spitless*, chicken-livered*, chicken-hearted*, afraid of one's own shadow*, wimpy*; see also cowardly 1.
Antonyms bold, fearless, confident.