Source : Webster's Revised Unabridged Dictionary (1913)

Elfin \Elf"in\ (-[i^]n), a.
   Relating to elves.

Elfin \Elf"in\, n.
   A little elf or urchin. --Shenstone.

Source : WordNet®

elfin
     adj 1: suggestive of an elf in strangeness and otherworldliness;
            "thunderbolts quivered with elfin flares of heat
            lightning"; "the fey quality was there, the ability to
            see the moon at midday"- John Mason Brown [syn: {fey}]
     2: small and delicate; "she was an elfin creature--graceful and
        delicate"; "obsessed by things elfin and small" [syn: {elflike}]
     3: relating to or made or done by or as if by an elf; "elfin
        bells"; "all the little creatures joined in the elfin
        dance"
     4: usually good-naturedly mischievous; "perpetrated a practical
        joke with elfin delight"; "elvish tricks" [syn: {elfish},
        {elvish}]