I was particularly delighted by Dorothy Burnham's realization of the word. I ran across this while looking it up in the Sherlock dictionary earlier tonight.
a. Having or displaying an otherworldly, magical, or fairylike aspect or quality: “She's got that fey look as though she's had breakfast with a leprechaun” (Dorothy Burnham).
b. Having visionary power; clairvoyant.
c. Appearing touched or crazy, as if under a spell.