Mischievous little creature (3)
I believe the answer is:
elf
'mischievous little creature' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for elf that I've seen before include "One of the little folk" , "Fairy, pixie" , "Robin Goodfellow?" , "Pixie (able to cobble?)" , "spirit" .)