Large ape (5-4)
'large ape' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for gorilla that I've seen before include "Big ape" , "Large animal" , "Large primate" , "Heavy" , "big mammal" .)
(Other definitions for orang-utan that I've seen before include "Great ape" , "Angora nut for long-armed ape of Burma" , "Endangered primate" , "Endangered ape" , "Anthropoid mammal of Indonesia" .)