Fairies, elves (6)
I believe the answer is:
pixies
This clue is a double definition.
'fairies' is the first definition.
(I know this)
'elves' is the second definition.
('pixy' can be a synonym of 'elf')
(Other definitions for pixies that I've seen before include "Mischievous fairies" , "Elves, imps" , "Little (mischievous) people" , "Small supernatural beings in fairy tales" , "small fairies in children's tales" .)