knock the wind out of sails

knock the wind out of (one's) sails

1. To diminish one's enthusiasm, excitement, or positive outlook (about something). Sorry, I didn't mean to knock the wind out of your sails or anything. I just don't want you getting your hopes up about this. It really knocked the wind out of his sails to learn that nearly half of his bonus would go to taxes.
2. To diminish one's momentum or motivation to succeed. You can tell that the crowd's deafening applause for the home team is starting to knock the wind out of their opponents' sails. The scandal knocked the wind out of their sails, and they trailed in the polls for the rest of the election.
See also: knock, of, out, sail, wind
Farlex Dictionary of Idioms.

knock the wind out of someone's sails

 
1. Lit. to bring someone to an abrupt halt by a heavy blow to the body, presumably knocking the person's wind out. (Alludes to a ship being slowed by positioning another ship to block off the wind from the first ship's sails.) Fred hit Mike and really knocked the wind out of his sails. Fred ran into the side of the garage and knocked the wind out of his sails.
2. Fig. to humiliate someone. The sharp rebuke from the boss knocked the wind out of his sails. That scolding really knocked the wind out of her sails.
See also: knock, of, out, sail, wind
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • knock the wind out of (one's) sails
  • take the wind out of (one's) sails
  • take the wind out of one's sails
  • take the wind out of sails
  • take the wind out of somebody's sails
  • take the wind out of someone’s sails
  • take the wind out of someone's sails
  • back and fill
  • back and fill, to
  • filling