What is the Japanese word for KO?

There isn't one single perfect Japanese word for "KO" in the sense of a knockout in boxing or martial arts. The meaning depends on the context. Here are a few options:

* ノックアウト (nokkuauto): This is the most straightforward translation, as it's a direct loanword from English. It's widely understood.

* KO (ケーオー): The English abbreviation is also commonly used in Japanese, particularly in sports reporting.

* You could also describe the situation using phrases like:

* 意識を失う (ishiki o usinau): To lose consciousness

* 気絶する (kizetsu suru): To faint

The best choice depends on the situation. For a boxing match report, ノックアウト (nokkuauto) or KO (ケーオー) would be ideal. If you're describing someone being knocked unconscious in a different context, 意識を失う (ishiki o usinau) or 気絶する (kizetsu suru) might be more appropriate.