Organ composition for big ape (5)
I believe the answer is:
orang
'big ape' is the definition.
(I've seen this in another clue)
'organ composition' is the wordplay.
'composition' indicates an anagram (letters arranged or composed in a different order).
'organ' with letters rearranged gives 'ORANG'.
'for' is the link.
(Other definitions for orang that I've seen before include "Large ape" , "Primate" , "Forest-dweller with red hair" , "- - -utan" , "Wild animal briefly appeared" .)