Knock it off: slang, To stop doing whatever one is doing, Often used as an imperative. To stop doing something. used to tell somebody to stop making a noise, annoying you, used to tell someone to stop doing something that you find annoying or foolish. If you tell someone to knock it off, you are telling them to stop doing something that is annoying you.
中文释义：knock 敲打， 敲；off离开，字面意思是不要再敲了，俚语一般是从字面意思引申而来的，所以Knock it off不难理解为少来这一套，别再讲下去。是很常用的一句俚语，用于告诉某人停止做烦人或愚蠢的事，也就是“住手；别闹了，住手(不要再做某事)”；与“Cut it out!”和“Stop it!”都是同样的意思，主要就是用来提醒某某不要再继续下去（无论是行为上还是语言上）。比如：一个很烦人的小孩子在乱蹦乱跳，旁边的姐姐看到了就说 “knock it off…”。