Request enjoyment? Not certainly (4)
I believe the answer is:
plea
'request' is the definition.
(plea is a kind of request)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for plea that I've seen before include "Urgent request" , "Earnest appeal" , "Urgent entreaty" , "suit" , "Excuse - pretext" .)