let it drop
1. To cease discussing or dwelling upon a given subject. Look, we can't afford a new car right now, so just let it drop already!
2. To accidentally or inadvertently reveal a given secret or important piece of information. I can't believe your sister let it drop that we're engaged in front of your parents!
let it rest
To cease discussing or dwelling upon a given subject. Look, we can't afford a new car right now, so just let it rest already!
let it slip
To accidentally or inadvertently reveal a given secret or important piece of information. We had done so well keeping our engagement a secret. I can't believe I let it slip in the middle of dinner last night!
let one rip
slang To fart loudly or profusely. I can't believe you let one rip in the car. Now we have to smell it all the way home!