The definition of a wiseguy is a smart-aleck who is annoying and full-of-himself, or a member of the Mafia or other organized crime syndicate.
An example of a wiseguy is an arrogant person at work who is always making sarcastic comments that he thinks are hysterical.
An example of a wiseguy is a man in the Mafia who has been made one of the crime bosses.
A person who is brashly and annoyingly conceited, knowing, etc.; smart aleck.
A hoodlum or gangster; esp., a member of the Mafia.
Alternative spelling of wise guy.