Primate is a bit of a gin drinker (5)
I believe the answer is:
indri
'primate' is the definition.
(I know that indri is a type of lemur)
'bit of a gin drinker' is the wordplay.
'bit of' says the answer is hidden in the clue.
'INDRI' is hidden in the letters of 'gin drinker'.
'is a' is the link.
(Other definitions for indri that I've seen before include "Madagascan mammal" , "Species of lemur" , "Big Madagascan lemur" , "Animal" , "native of Madagascar" .)