Monkey business 意為「惡作劇；胡鬧；騙人的把戲；詭計」(mischief, shenanigans)，所以這個慣用語可能指無傷大雅的胡鬧或不懷惡意的搗蛋，但也可能指欺騙的、不誠實的或不道德的惡作劇、把戲、詭計或詐騙。
這個慣用語於 1800 年代中期開始使用，源自梵文 (Sanskrit) 的 vānara-karman，這用語可翻譯成 monkey action 或 monkey work。
例句：
- Please stop the monkey business and get to work! (別胡鬧了，開始工作吧！)
- The boss suspected that there had been some monkey business going on while he went on a business trip to Japan. (老闆懷疑他去日本出差時有人搞惡作劇)
- I don’t believe such a ridiculous thing could have happened. I think you are only playing monkey business with me. (我不相信會發生這麼荒謬的事情，我認為你是在跟我惡作劇)
- We know there was a lot of monkey business with counting ballots in the previous presidential election. (我們都知道，在上次的總統選舉中，選票的計算有許多陰謀詭計)
- There’s money missing from the office and it’s not the first time it’s happened. I think there’s some monkey business going on. (辦公室掉了錢，而這不是第一次發生。我想有人在搞鬼)