knock-backBrE /ˈnɒk bæk/ 🔊NAmE /ˈnɑːk bæk/ 🔊 noun (informal) a difficulty or problem that makes you feel less confident that you will be successful in sth that you are doing, especially when sb rejects you or sth you suggest or ask （尤指被人拒绝时受到的）挫折，挫伤，打击