take the wind out of one's sails

take the wind out of one's sails  {v. phr.}

To surprise someone by doing better or by catching him in an error.

John came home boasting about the fish he had caught; it took the wind out of his sails when he found his little sister had caught a bigger one.

Dick took the wind out of Bob's sails by showing him where he was wrong.

Compare: TAKE THE STARCH OUT OF (2).