noun, noun or participle which takes 'suru', transitive verb
Used in boxing, martial arts, and similar contexts for a knockdown. Also used as a suru-verb meaning 'to knock down'.
彼は試合で相手をノックダウンした。
He knocked down his opponent in the match.
ノックダウンから立ち上がった。
He got up from the knockdown.
ダウン is a more general term for 'down' or 'fall', while ノックダウン specifically refers to a knockdown in a fight or competition.
Loanword from English 'knockdown'.