Meaning of “tip sb off” - Learner’s Dictionary

tip sb off

phrasal verb with tip us uk /tɪp/ verb present participle tipping, past tense and past participle tipped

to warn someone secretly about something so that they can take action or prevent it happening

tip-off noun [ C ] us uk /ˈtɪpɒf/

a piece of information that you give someone secretly, so that they can take action or prevent something happening

(Definition of “tip sb off” from the Cambridge Learner’s Dictionary © Cambridge University Press)