hate someone's guts

Thoroughly despise someone, as in I hate Peter's guts. The guts here refers to a person's inner essence. [Slang; c. 1900]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.