elfin (adj.)

"of or pertaining to elves," 1590s, from elf; first found in Spenser, who also used it as a noun and might have been thinking of elven but the word also is a proper name in the Arthurian romances (Elphin).

Others are reading

Definitions of elfin from WordNet

elfin (adj.)
suggestive of an elf in strangeness and otherworldliness; "the fey quality was there, the ability to see the moon at midday"- John Mason Brown;
thunderbolts quivered with elfin flares of heat lightning
Synonyms: fey
elfin (adj.)
small and delicate;
she was an elfin creature--graceful and delicate
obsessed by things elfin and small
Synonyms: elflike
elfin (adj.)
relating to or made or done by or as if by an elf;
all the little creatures joined in the elfin dance
elfin bells
elfin (adj.)
usually good-naturedly mischievous;
perpetrated a practical joke with elfin delight
Synonyms: elfish / elvish