give someone a tip—
1. give a gift of money to a waiter, porter, etc.:
- I gave him a tip, a small one, because I try to be nice to the people who make me angry.
2. provide a person with privileged information likely to bring useful results:
- Some politicians gave him a tip that Prohibition was starting to lose ground.
give someone a tip-off — = give someone a tip 2:
- A while ago a guy I met gave me a tip-off about a secluded beach somewhere in Goa.