cocksure/cocky

this is used of both sexes although it comes from the male fowl and tends to be used more often of men. If you want a sex-neutral term, use self-confident, overconfident, arrogant, self-important, in love with oneself, pushy, overbearing, swaggering, aggressive, conceited, haughty, supercilious; jaunty, brash, cheeky, flippant, saucy, nervy, impertinent, insolent, careless.