Primate blessing sailor brought inside (6)
I believe the answer is:
baboon
'primate' is the definition.
(baboon is a kind of primate)
'blessing sailor brought inside' is the wordplay.
'blessing' becomes 'boon' (synonyms).
'sailor' becomes 'ab' (abbreviation for able seaman).
'brought inside' indicates putting letters inside.
'boon' going around 'ab' is 'BABOON'.
(Other definitions for baboon that I've seen before include "Stupid person" , "Large primate" , "Large monkey with a doglike muzzle" , "clumsy uncouth person" , "Large long-nosed African or Asian monkey" .)