Copies of mushy peas (4)
I believe the answer is:
apes
'copies' is the definition.
('ape' can be a synonym of 'copy')
'mushy peas' is the wordplay.
'mushy' indicates an anagram (letters mushed up).
'peas' with letters rearranged gives 'APES'.
'of' acts as a link.
(Other definitions for apes that I've seen before include "Copies the primates?" , "Peas (anag)" , "Imitates like primates" , "Imitates in every aspect" , "Parrots" .)