Pixies, imps (5)
I believe the answer is:
elves
This clue is a double definition.
'pixies' is the first definition.
('elf' can be a synonym of 'pixie')
'imps' is the second definition.
('elf' can be a synonym of 'imp')
(Other definitions for elves that I've seen before include "Little mischievous fairies" , "Mythical beings" , "mischievous kids?" , "Santa's little helpers" , "Imps, pixies" .)