Parasite from the Capital of South Korea, possibly (5)
I believe the answer is:
louse
'parasite' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for louse that I've seen before include "Common parasite on animals" , "Rogue" , "Parasite; nasty person" , "Unpleasant person" , "Wingless bloodsucker" .)