a wise guy

(American & Australian informal) also a wise-ass (American very informal!)

someone who is always trying to seem more clever than everyone else in a way that is annoying Okay, wise guy, if you're so damned smart, you can tell everyone how it's done! He's just some wise-ass who thinks he knows all the answers. (American & Australian informal)

See an old head on young shoulders

Common Names:

Name	Pronounced	Usage
Imen	-	Arabic
LÉOntine	-	French
Maha	-	Arabic
SafİYe	-	Turkish
Carla	['ka:lə]
Dharma	-	Indian, Hindi, Telugu, Nepali