knockout

About 0.71 uses per million words.

Meaning

noun 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.
The boxer scored a knockout on his opponent.
noun The deactivation of anything.
noun Something wildly popular, entertaining, or funny.
If you've ever had a sack race, you know it's a real knockout for kids and adults alike.
noun A very attractive person, especially a beautiful woman.
noun A partially punched opening meant for optional later removal.
They left a knockout in the panel for running extra wires someday.
noun The deactivation of a particular gene.
noun A creature engineered with a particular gene deactivated.
noun An event where a foreground color causes a background color not to print.