Informal. a cocksure, conceited, and often insolent person; smart aleck: He has a reputation for being a wise guy.
Origin of wise guy
An Americanism dating back to 1895–1900
Also called wiseacre.
Related formswise-guy, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for wise guy
informal a person who is given to making conceited, sardonic, or insolent comments
US a member of the Mafia
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Idioms and Phrases with wise guy
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.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.