1520s, "certain," from cock (n.1) + sure (adj.). Probably "as assured as a cock." "The word was originally perfectly dignified, and habitually used in the most solemn connexions" [OED].
权威例句
1. He is too bloody cocksure about everything.
他对于每一件事都过于自信.
2. Don't be so cocksure that he will succeed.
不要那么确信他会成功.
3. [ Little ] Where's the cocksure sky jock I had last week?
上星期那个可靠的飞行员到哪里去了?
4. He's so cocksure I'd love to see him proved wrong.
他过分自信--我 倒 想看看他栽跟头.
5. Don't be too cocksure and take things for granted.