Stammer badly describing love for Primate (8)
I believe the answer is:
marmoset
'primate' is the definition.
(marmoset is a kind of primate)
'stammer badly describing love' is the wordplay.
'badly' indicates anagramming the letters.
'describing' is an insertion indicator (describe can mean to form the outline of).
'love' becomes 'o' (In tennis, 'love' means 'zero').
'stammer' anagrammed gives 'marmset'.
'marmset' enclosing 'o' is 'MARMOSET'.
'for' acts as a link.
(Other definitions for marmoset that I've seen before include "Little monkey" , "Small bushy-tailed monkey" , "Primate" , "Turn morse mat over for the monkey" , "Monkey with claws" .)