That knocks out; characterized by knocking out; as, a knock-out blow; a knock-out key for knocking out a drill from a collet.
- The act of knocking out.
- The state of being knocked out.
- A blow that knocks out an opponent.
- Sports A victory in boxing in which one's opponent is unable to rise from the canvas within a specified time after being knocked down or is judged too injured to continue.
- Sports The act of winning a boxing match in this way: won the fight by a knockout.
- Slang A strikingly attractive or impressive person or thing.
- Capable of knocking out: a knockout punch.
- Strikingly attractive or impressive.
- Having a specific single gene removed from the genome by genetic manipulation: knockout mice used in an experiment.