Idioms :

a big mouth informal
someone cannot keep a secret:
• That girl has a big mouth.
• I'm sorry. I shouldn't have opened my big mouth.
• me and my big mouth (= said when you wish you had not told someone a secret)
• Who's the big mouth who told Carole about her surprise birthday party?
Helen's got such a big mouth - the news'll be all over the town by tonight.
I knew I shouldn't have mentioned the letter. Oh dear, me and my big mouth!
Dave's a real big-mouth, so don't tell him anything.
He is/has such a big mouth.
He went and opened his big mouth and told them the whole story.
drop sb a line INFORMAL
to write and send a short letter to someone:
• Drop us a line sometime.
Just drop me a line when you've decided on a date.
drop (sb) a hint INFORMAL
to tell someone something in an indirect way
• I've dropped a few hints about what I want for my birthday.
Margaret dropped a hint that she'd like to come to the party.
He dropped a few hints about some gifts he'd like to get.
name-dropping noun [U] DISAPPROVING
when someone talks about famous people that they have met, often pretending that they know them better than they really do, in order to appear more important and special
name drop verb [I] DISAPPROVING
name-dropper noun [C] DISAPPROVING

a drop in the ocean UK (US a drop in the bucket)
a very small amount compared to the amount needed
• Five thousand is a drop in the bucket compared to the $14 million we need.
My letter of protest was just a drop in the ocean.
We were paid about $50,000, but that was a drop in the bucket compared to what some other companies got.
drop the ball
to not do a job that you are expected to do, especially because you make mistakes:
• Investigators dropped the ball in the murder investigation