Chimpanzee or human (3)
I believe the answer is:
ape
I believe this clue is a double definition.
'chimpanzee' is the first definition.
(thesaurus)
'human' is the second definition.
(ape is a kind of human)
(Other definitions for ape that I've seen before include "Anthropoid primate" , "drill" , "Imitate like primate" , "Idiot" , "Our cousin" .)