foul one's (own) nest

do something damaging or harmful to oneself or one's own interests

破坏（或伤害）自己（或自己的利益）

foul something up ( 或 foul up)

make a mistake with or spoil something

把…搞糟；搞乱

leaders should admit when they completely foul things up.

领导人把事情完全搞糟时应该自己承认。

foul out

&I{Sports} To be put out of a game for exceeding the number of permissible fouls.

&I{【体育运动】} 因犯规超过规定次数被罚下场

foul up

To blunder or cause to blunder because of mistakes or poor judgment.

因错误或粗心而犯大错