give (something) the thumbs down

To show one's disapproval of something. The phrase can refer to the actual gesture, which carries the same meaning, but is typically used figuratively. I know the committee approved our idea, but the CEO ultimately gave it the thumbs down.

COMMON If you give a plan, suggestion, or activity the thumbs down, you show that you do not approve of it and are not willing to accept it. Out of 58,000 replies, 79 per cent gave the thumbs down to the idea of votes for prisoners. Note: You can also say that something gets the thumbs down. Unlicensed boxing is dangerous for the individuals involved, dangerous for the sport and gets a firm thumbs down from me. Note: A thumbs down or a thumbs-down sign is a sign that you make by pointing your thumb downwards in order to show dissatisfaction or disagreement, or to show that things are going badly. In ancient Rome, a signal in which the thumb was bent down was used at the games to tell a victorious gladiator not to kill his opponent.