what is the meaning of a thump up sign
thumbs up. 1. n. a sign of approval. It was a thumbs up on the new filtration plant at Thursdayâs village board meeting. 2. mod. approving; positive. The new filtration plant got a thumbs up decision at the board meeting.. a sign of approval. It was a thumbs up on the new filtration plant at Thursday's village board meeting. There was no thumbs up for the mayor as she faced certain defeat in today's balloting. 2. approving; positive.