wake–up call

something that tells of approaching danger or risk his high blood pressure was a wake-up call that he needed to do something about his health Synonyms caution, red flag, red light, tip-off, tocsin, wake-up callRelated Words omen, portent, premonition, presage; notice, notification; buoy, indicator, knell, sign, signal; foretaste, foretoken; announcement, declarationNear Antonyms all clear