Copies from a month back (4)
I believe the answer is:
apes
'copies' is the definition.
('ape' can be a synonym of 'copy')
'a month back' is the wordplay.
'month' becomes 'sep' (Sep is an example**).
'back' says the letters should be written in reverse.
'sep' back-to-front is 'pes'.
'a'+'pes'='APES'
'from' is the link.
(Other definitions for apes that I've seen before include "Species of primate" , "Imitates like primates" , "Peas (anag)" , "Copies the primates?" , "Mimics like primates" .)