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 drop (or rest)
say or do no more about a matter or problem. let it
/'er rip Informal To allow something to start or happen with vigor or energy.