take the wind out of somebody’s sails
From Longman Dictionary of Contemporary Englishtake the wind out of somebody’s sailstake the wind out of somebody’s sailsinformalCONFIDENT to make someone lose their confidence, especially by saying or doing something unexpected → windExamples from the Corpustake the wind out of somebody’s sails• Last night's defeat has taken some of the wind out of the team's sails.