To act in a way that is contrary to one's goals or intentions; to defeat one's own purpose.
他想节省开支，却又不停地购买奢侈品，真是北辙南辕。
He wants to save money, yet he keeps buying luxury goods; he's truly defeating his own purpose.
Next Idiom
To act in a way that is contrary to one's goals or intentions; to defeat one's own purpose.