Little devils being wicked, neglecting debt notice (4)
I believe the answer is:
imps
'little devils' is the definition.
(I've seen this in another clue)
'wicked neglecting debt notice' is the wordplay.
'wicked' becomes 'impious' (associated in meaning).
'neglecting' indicates named letters should be taken away.
'debt notice' becomes 'iou' (I've seen this in another clue).
'impious' with 'iou' removed is 'IMPS'.
'being' is the link.
(Other definitions for imps that I've seen before include "Troublemakers" , "Demons" , "Mischievous spirits" , "repairs (for a wing)" , "naughty children" .)