Korean martial art (3,4,2)
'korean martial art' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tae kwon do that I've seen before include "Martial activity" , "Koreans fighting" , "combat" , "Martial art Olympic event since 2000" , "Martial art display" .)
(Another definition for taekwondo that I've seen is " event".)