done deal

plural done deals

1. idiomaticAn agreement that has been finally resolved or decided.

   It's a done deal — he already sold me the prize wine bottle from his collection, and I already popped the cork.

   1 more example

   “You get a win and suddenly the crowd’s on your side again. It was a shot in the arm for two reasons. First, when we work together, we are stronger. Second, this isn’t a done deal.”

   2018 April 28, Dorian Lynskey, quoting James McGrory, “‘It’s not a done deal’: inside the battle to stop Brexit”, in The Guardian

   Synonyms: done dotta

2. idiomaticAn established fact that cannot be undone.

   Near-synonyms: fait accompli, water under the bridge

   1 more example

   They're telling us that climate change is a done deal — that now we're into mitigation and adaptation instead of prevention.

   Synonyms: fait accompli, water under the bridge