Big brutes (4)
I believe the answer is:
apes
'big brutes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for apes that I've seen before include "Species of primate" , "Copies the primates?" , "Imitates like primates" , "Zoo animals" , "Imitates in every aspect" .)