Monkey proves a benefit to graduate (6)
I believe the answer is:
baboon
'monkey' is the definition.
(baboon is a kind of monkey)
'benefit to graduate' is the wordplay.
'benefit' becomes 'boon' (I've seen this in another clue).
'to' means one lot of letters go next to another (I've seen this in other clues).
'graduate' becomes 'BA' (someone with a Bachelor of Arts degree).
'boon' after 'ba' is 'BABOON'.
'proves a' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for baboon that I've seen before include "A large one of 17 across" , "Large long-nosed African or Asian monkey" , "Type of large monkey" , "Stupid person" , "Large primate" .)