cut (someone or something) down to size
1. To criticize one in an attempt to deflate their ego. A: "That guy always dominates the class discussion with his rambling, inane thoughts like he's some genius." B: "I know! It's time to cut him down to size."
2. To minimize the importance of something. We need to cut the board down to size before they continue their pattern of overreach.
cut somebody down to ˈsize
show that somebody is less important than they seem or think: Failing his exams has certainly cut him down to size.