knockout
[noun]
Synonyms:
- killer blow, coup de grâce, KO or K.O. (slang)
- success, hit, sensation, smash, smash hit, triumph, winner

[TahlilGaran] English Synonym Dictionary ▲

I. knock‧out¹ /ˈnɒk-aʊt $ ˈnɑːk-/ noun [countable]

1. when a boxer hits his opponent so hard that he falls down and cannot get up again:
The fight ended in a knockout.

2. informal someone or something that is very attractive or successful:
Her dress was a knockout.

3. a type of competition in which only the winning players or teams at each stage continue to play until there is only one winner

[TahlilGaran] Dictionary of Contemporary English ▲

II. knockout² adjective informal

1. knockout punch/blow
a) a hard hit that knocks someone down so that they cannot get up again
b) an action or event that causes defeat or failure:
High interest rates have been a knockout blow to the business.

2. relating to a type of competition in which only the winning players or teams at each stage continue to play:
Scotland’s failure to get through the knockout stage of the competition

3. knockout pills/drops etc pills etc that make someone unconscious

[TahlilGaran] Dictionary of Contemporary English ▲

knockout
n., slang
1. Strikingly beautiful woman.
Sue is a regular knockout.
2. A straight punch in boxing that causes one's opponent to fall and lose consciousness.
The champion won the fight with a straight knockout.

[TahlilGaran] English Idioms Dictionary ▲