Revolting characters in quality Alpine drama (4)
I believe the answer is:
play
'drama' is the definition.
(I know that drama can be written as play)
'revolting characters in quality alpine' is the wordplay.
'revolting' shows that the letters should be reversed in order.
'characters in' says the answer is hidden in the clue.
'yalp' is hidden within 'quality alpine'.
'yalp' written backwards gives 'PLAY'.
(Other definitions for play that I've seen before include "stage production" , "Theatre performance" , "Have fun -- theatrical work" , "Dramatic work" , "Amuse oneself - drama" .)