take the wind out of someone's sails

verb1

•
To discourage someone greatly; to cause someone to lose hope or the will to continue; to thwart or minimize someone's ambitions.
- "I tell you Van Bahr Lamb is a fool." […] But Polly […] completely took the wind out of her sails, by coolly remarking,— "I like fools." — 1860

forms

took the wind out of someone's sails · taken the wind out of someone's sails · taking the wind out of someone's sails · takes the wind out of someone's sails