cocksure

1 displaying or marked by rude boldness his cocksure assertion that he could bed any woman of his choice Synonyms arch, audacious, bold, bold-faced, brash, brassbound, brassy, brazen, brazen-faced, cheeky, nervy, cocky, fresh, impertinent, impudent, insolent, sassy, saucy, wiseRelated Words assertive, forward, obtrusive; audacious, defiant, disrespectful; shameless, unabashed, unblushing; bluff, blunt, curt; cute, facetious, flip, flippant, pert, smart, smart-aleck, smart-alecky; lippy, mouthyNear Antonyms demure, humble, modest; courteous, genteel, mannerly, polite, proper; deferential, respectful; abashed, ashamed, blushing, embarrassed, shamefaced; gentle, mild; inconspicuous, unobtrusiveAntonyms meek, mousy (or mousey), retiring, shy, timid

2 having or showing a mind free from doubt you're always so cocksure about everything Synonyms assured, clear, certain, confident, doubtless, implicit, positive, sanguine, sureRelated Words self-assured, self-conceited, self-confident; decisive, resolute, unfaltering, unhesitating, unquestioning, unwaveringNear Antonyms hesitant, indecisive, vacillating, wavering; diffident, unassumingAntonyms doubtful, dubious, uncertain, unsure