A demonic, funny entertainer (8)
I believe the answer is:
comedian
'entertainer' is the definition.
(comedian is a kind of entertainer)
'a demonic funny' is the wordplay.
'funny' indicates an anagram.
'a'+'demonic'='ademonic'
'ademonic' with letters rearranged gives 'COMEDIAN'.
(Other definitions for comedian that I've seen before include "Joker" , "I'm not taken seriously" , "Hope, perhaps" , "One tells jokes" , "scream?" .)