elf·in 
(ĕlfĭn)
(ĕlfĭn)adj.
1.
a. Relating to or suggestive of an elf.
b. Made, done, or produced by an elf.
2. Small and sprightly or mischievous.
3. Having a magical quality or charm; fairylike: moved across the dimly lit stage with elfin grace.
[Probably from Middle English elvene, pl. of elve, elf, from Old English -elfen (as in wuduelfen, dryad); see albho- in the Appendix of Indo-European roots.]