Chap contributing to informal entertainment (4)
I believe the answer is:
male
'chap' is the definition.
(I've seen this in other clues)
'contributing to informal entertainment' is the wordplay.
'contributing to' says the answer is hidden in the clue.
'MALE' can be found hidden inside 'informal entertainment'.
(Other definitions for male that I've seen before include "A gender" , "Maldives capital; masculine" , "As are drakes, bulls etc." , "man?" , "Lame sort of fellow" .)