Short feel, entertaining partner, is unprofessional (7)
I believe the answer is:
amateur
'unprofessional' is the definition.
(synonyms)
'short feel entertaining partner' is the wordplay.
I cannot really see how this works, but
'partner' could be 'mate' (synonyms) and 'mate' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'is' is the link.
Can you help me to learn more?
(Other definitions for amateur that I've seen before include "Not pro" , "enthusiast" , "Receiving no money" , "Engaged in as a pastime" , "Unpaid (sportsman}" .)