The western one is pale (3)
I believe the answer is:
wan
'pale' is the definition.
('wan' can be a synonym of 'pale')
'the western one' is the wordplay.
'the western' becomes 'w'.
'one' becomes 'an' (I've seen this in other clues).
'w'+'an'='WAN'
'is' acts as a link.
(Other definitions for wan that I've seen before include "Pale as from illness" , "Lacking colour" , "Pale; weak" , "Pale, looking tired" , "Looking pale and sickly" .)