From Longman Dictionary of Contemporary Englishtip somebody ↔ off phrasal verbTELLWARNto give someone such as the police a secret warning or piece of information, especially about illegal activities The police must have been tipped off.tip somebody off that His contact had tipped him off that drugs were on the premises. about Did you tip him off about Bernard? → tip→ See Verb table
Examples from the Corpustip off• There are 7-8 distinctly flattened, finely rugose arm spines, with the tips squared off.• Ralph had tipped Grover off about the developer being in over his head.• For instance, Charles Harvey has tipped her off about the new motorway but she pretends she doesn't know.• Some one should have tipped these people off before they opted for the independent life.• The agent who tipped them off had joined their escape into the woods.• Bonanza tips me off that Vecchi killed Mahoney.• As I raised my tips and slid off the lift, I wondered how I was going to get down the mountain.• Swanepoel, the pilot whom I had met when I first arrived in the country, tipped me off to that one.tip somebody off that• His contact had not merely tipped him off that drugs were on the premises, he had told him where to look.• Bonanza tips me off that Vecchi killed Mahoney.tip-offˈtip-off noun [countable] 1 informalWARN a secret warning or piece of information, especially one given to the police about illegal activities The arrests came after a tip-off from a member of the public.2 American English informal something that shows you that something is true, even though you did not expect it to be true The fact that he hasn’t called should be a tip-off that he’s not interested.3 the beginning of a basketball game, when the ball is thrown into the air and two players jump up to try to gain control of it
Examples from the Corpustip-off• Tip-off is at 7:30 tonight in the Coliseum.• Police were called to the hotel after a tip-off.• The fact he hasn't called should be a tip-off that he's not interested.• The raid had been anticipated for months following a tip-off to the Metropolitan police.• Unusual swimming patterns are often a tip-off that a whale is in danger.• Acting on a tip-off, customs officers seized 50 kilos of cocaine from a house in Leicester.• Acting on a tip-off, they searched the car and its occupants.• There was a climate of fear after anonymous tip-offs claiming that live weapons would be used.• A sure tip-off that you have structural problems is repeated ideas.• Even if the tip-off is anonymous, make it.• The tip-off is your focus on performance that needs improvement, rather than focusing on your successes.