The Collaborative International Dictionary of English v.0.48:

Elves \Elves\, n.; pl. of Elf.
   [1913 Webster] Elvish \Elv"ish\, a.
   1. Pertaining to elves; implike; mischievous; weird; also,
      vacant; absent in demeanor. See Elfish.
      [1913 Webster]

            He seemeth elvish by his countenance. --Chaucer.
      [1913 Webster]

   2. Mysterious; also, foolish. [Obs.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

elvish
    adj 1: usually good-naturedly mischievous; "perpetrated a
           practical joke with elfin delight"; "elvish tricks" [syn:
           elfin, elfish, elvish]

The Jargon File (version 4.4.7, 29 Dec 2003):

elvish
 n.

    1. The Tengwar of Feanor, a table of letterforms resembling the beautiful
    Celtic half-uncial hand of the Book of Kells. Invented and described by J.
    R. R. Tolkien in The Lord of The Rings as an orthography for his fictional
    ?elvish? languages, this system (which is both visually and phonetically 
    elegant) has long fascinated hackers (who tend to be intrigued by
    artificial languages in general). It is traditional for graphics printers,
    plotters, window systems, and the like to support a Feanorian typeface as
    one of their demo items. See also elder days.

    2. By extension, any odd or unreadable typeface produced by a graphics
    device.

    3. The typeface mundanely called ?B?cklin?, an art-Noveau display font.


The Free On-line Dictionary of Computing (30 December 2018):

elvish

    1. The Tengwar of Feanor, a table of letterforms
   resembling the beautiful Celtic half-uncial hand of the "Book
   of Kells".  Invented and described by J.R.R. Tolkien in "The
   Lord of The Rings" as an orthography for his fictional
   "elvish" languages, this system (which is both visually and
   phonetically elegant) has long fascinated hackers (who tend
   to be intrigued by artificial languages in general).  It is
   traditional for graphics printers, plotters, window systems,
   and the like to support a Feanorian typeface as one of their
   demo items.  By extension, the term might be used for any odd
   or unreadable typeface produced by a graphics device.

   2. The typeface mundanely called "B"ocklin", an art-decoish
   display font.  [Why?]

   [Jargon File]

   (1998-04-28)