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
Linnet	li-NET, LIN-ət	English (Rare)
Bonaventure	bawn-ə-VEN-chər (English)	History
Mick	MIK (English)	English, Dutch
Fayvel	-	Yiddish
Onur	-	Turkish
Soroush	-	Persian Mythology, Persian