caution /ˈkɔːʃ(ə)n/noun 6verb 3forms 4phrases 1 noun6 •Prudence when faced with, or when expecting to face, danger; care taken in order to avoid risk or harm.have cautionutmost caution is required when travelling in this dangerous neighbourhood •A careful attention to the probable effects of an act, in order that failure or harm may be avoided.The guideline expressed caution against excessive radiographic imaging. •A formal warning given as an alternative to prosecution in minor cases. •A yellow card. •(old-fashioned) One who draws attention or causes astonishment by their behaviour.Oh, that boy, he's a caution! He does make me laugh. •Security; guaranty; bail.The Parliament would yet give his majesty sufficient caution that the war should be vigorously prosecuted. — 1702 verb3 •To warn; to alert, advise that caution is warranted."Careful, Uwe," cautions my Venezuelan explorer friend, José Miguel Pérez, with a grim smile. "You're too big for us to carry back down." — 1989 •To give a yellow card. •(UK) To read someone their formal legal rights as part of a lawful arrest.They're under arrest. Caution them, will you? — 1999 formscautioned · cautioning · cautioneth · cautions Phrases with caution throw caution to the windTo do something despite the risks.