tip someone off Definition

tip³
noun

1. A gift of money given to a servant or waiter, etc in return for service done well.

Thesaurus: gratuity, compensation, reward.
2. A piece of useful information; a helpful hint or warning.

Thesaurus: information, hint, pointer, suggestion, knowledge, advice, inside information, dope (slang), lowdown (slang).
3. A piece of inside information which may lead to financial gain, such as the name of a horse likely to win a race.

verb

tipped, tipping
1. To give a tip to someone.

Etymology: 17c: perhaps a special use of tip⁴.

Phrasal Verb: tip someone off

To give them a piece of useful or secret information. See also tip-off.