The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with mop up the floor with
mop up the floor with
Also,wipe the floor with. Defeat thoroughly, overwhelm, as in The young boxer said he was sure to mop up the floor with his opponent, or I just know we'll wipe the floor with the competition.
[ Late 1800s