Gorillas or gibbons, eg (4)
I believe the answer is:
apes
I believe this is a double definition.
'gorillas' is the first definition.
(gorillas are apes)
'gibbons eg' is the second definition.
(gibbon is a kind of ape)
(Other definitions for apes that I've seen before include "Zoo animals" , "Large primates" , "Imitates like primates" , "Peas (anag)" , "Imitates in every aspect" .)