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what's done is done

Idioms  

  1. There is no changing something; it's finished or final. For example, I forgot to include my dividend income in my tax return but what's done is done—I've already mailed the form. This expression uses done in the sense of “ended” or “settled,” a usage dating from the first half of the 1400s.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

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