knockout

Short definition from Wiktionary

Noun

1. 1
   The act of making one unconscious, or at least unable to come back on one's feet within a certain period of time; a TKO.
2. 2
   The deactivation of anything.
3. 3
   Something wildly popular, entertaining, or funny.
4. 4
   A very attractive person, especially a beautiful woman.
5. 5
   A partially punched opening meant for optional later removal.
6. 6
   The deactivation of a particular gene.
7. 7
   A creature engineered with a particular gene deactivated.
8. 8
   An event where a foreground color causes a background color not to print.
9. 9
   A tournament in which a team or player must beat the opponent in order to progress to the next round.
10. 10
    A simple game for two or more players, derived from basketball.
11. 11
    A woman in Total Nonstop Action Wrestling.
12. 12
    Ellipsis of knockout auction.

Adjective

1. 1
   Rendering someone unconscious.
2. 2
   Amazing; gorgeous; beautiful.
3. 3
   Designating an organism in which a particular gene has been removed or deactivated.
4. 4
   Causing elimination from a competition.