Angels hear imps misbehaving (8)
I believe the answer is:
seraphim
'angels' is the definition.
(seraph is a kind of angel)
'hear imps misbehaving' is the wordplay.
'misbehaving' indicates an anagram.
'hear'+'imps'='hearimps'
'hearimps' with letters rearranged gives 'SERAPHIM'.
(Other definitions for seraphim that I've seen before include "High-ranking angels" , "Angelic beings" , "Angels of the highest rank" , "High spirits" , "Angelic types" .)