a hostile or dangerous person.
Political Euphemisms: The Good, The Bad, The UglyRead more in this article about some frequently asked questions and fun facts related to our definitions.
Ridiculous Clichés Athletes Use After Every GameRead more in this article about some frequently asked questions and fun facts related to our definitions.
Origin of ugly customer
First recorded in 1805–15
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
An ill-natured or vicious individual, as in Watch out for Charlie when he's drinking; he can be an ugly customer. This phrase uses ugly in the sense of “mean” or “dangerous.” [c. 1800]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.