- 敲出来，敲空(烟斗)；打掉：
I knocked the nail out.
我把钉子敲了出来。
to knock out a pipe
敲空烟斗
- 击昏，使不省人事；【拳击】击倒(对手)(使其在规定时间内无法站立)：
The ball hit him on the head and knocked him out.
球击中了他的头部，把他打昏了。
- (竞赛中)淘汰：
The boxer was knocked out in the second round.
该拳击手在第二个回合中被淘汰了。
- 使精疲力尽；累垮：
Don't knock yourself out with hardwork.
不要太辛苦而把自己累垮。
- 击败；摧毁；使失去功效，破坏掉：
to knock out the enemy guards
摧毁敌人警戒
The government decided to knock out gambling.
当局决定取缔赌博活动。
Telephone communications had been knocked out.
电话联系已被切断。
- (药物)使失去知觉；使昏睡：
The sleeping pills soon knocked the patient out.
安眠药片很快使病人昏睡过去了。
- [口语]匆促完成；胡乱演奏：
He knocked out the short story in one month.
他只用了一个月时间匆匆写完了那部短篇小说。
He's not a very accomplished pianist, but he can knock out a tune.
他不是一个造诣很深的钢琴家，但他可以胡乱演奏一曲。
- [口语]给…深刻印象；使震惊：
Her beauty knocked him out.
她的美貌使他为之倾倒。
The unexpected news knocked me out.
这个出乎意外的消息让我大为吃惊。
- 引起共鸣：
The book really knocks me out.
这本书确实引起了我的共鸣。
- 【棒球】打掉(投手)(进攻队一再打出好球迫使对方更换投手)
- 转卖低价买进的拍卖品(取得利润)