“马失前蹄”，汉语成语，本指马匹奔跑时前蹄弯折（the horse stumbles，the horse trips）；后引申为失算、栽跟斗，发生差错而受挫。可以翻译为“suffer an accidental setback，make a mistake by accident”。
例句：
此人一辈子做事小心谨慎，但也有马失前蹄的时候。
This man has been cautious all his life, but he’s nonetheless slipped occasionally.