Fitting part of expert in entertainment (9)
I believe the answer is:
pertinent
'fitting' is the definition.
(I've seen this before)
'part of expert in entertainment' is the wordplay.
'part of' says the answer is hidden in the clue.
'PERTINENT' is hidden within 'expert in entertainment'.
(Other definitions for pertinent that I've seen before include "Appropriate" , "fitting" , "Relevant, to the point" , "Apposite" , "Relevent, material" .)