|1.||informal a person who is given to making conceited, sardonic, or insolent comments|
|2.||(US) a member of the Mafia|
wise guy definition
An obnoxious know-it-all, a person who makes sarcastic or annoying remarks, as in the teacher was delighted that the worst wise guy in the class was moving out of town. [Slang; second half of 1800s] Also see smart aleck.