smarty-pants
noun/ˈsmɑːti pænts/
/ˈsmɑːrti pænts/
(British English also smart alec, North American English smart aleck)
(also British English, offensive smart-arse, North American English smart-ass)
(informal, disapproving)- a person who thinks they are very clever and likes to show people this in an annoying way
Check pronunciation:
smarty-pants