be cocksure of (oneself)

To be completely certain of oneself or one's actions, to the point of overconfidence. You seem pretty cocksure of yourself—do you really know how to handle that machine?

Common Names:

Name	Pronounced	Usage
Amichai	-	Hebrew
PacÍFica	pah-THEE-fee-kah (Spanish), pah-SEE-fee-kah (Latin American Spanish)	Spanish
Dixie	['diksi]
Reece	-	Welsh
Iona (1)	ie-ON-ə (English)	English, Scottish
Svein	-	Norwegian