swallow one's words
Take back what one said, as in If they win I'll have to swallow my words. George Farquhar used this idiom in The Inconstant (1702): “I have swallowed my words already; I have eaten them up.” For a synonym, see eat one's words.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.