Disheartened South Indian is bottom (4)
I believe the answer is:
tail
'bottom' is the definition.
('tail' can be a synonym of 'bottom')
'disheartened south indian' is the wordplay.
'disheartened' means to remove the middle letters.
'south indian' becomes 'tamil' (I've seen this before).
'tamil' with its centre removed is 'TAIL'.
'is' acts as a link.
(Other definitions for tail that I've seen before include "Follow -- rear end" , "Follow - rear part of aeroplane" , "Follow - dog" , "part of coat" , "Comet's luminous trail" .)