Repulsive, especially to the sight; revoltingly ugly. See Synonyms at ugly.(adjective)
Offensive to moral sensibilities; despicable.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "hideous" in a sentence
"Pretty much all of this has what you describe as hideous consequences."
""Interesting" is what you call the hideous dress one's wife asks you to critique."
"Even more hideous is the declared involvement in these proceedings at Guantánamo of qualified medical practitioners."