1. [n]  someone who believes in the existence of realities beyond human comprehension
2. [adj]  having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding; "mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients"
3. [adj]  relating to or characteristic of mysticism; "mystical religion"
4. [adj]  relating to or resembling mysticism; "mystical intuition"; "mystical theories about the securities market"

MYSTIC is a 6 letter word that starts with M.

1. \Mys"tic\, Mystical \Mys"tic*al\, a. [L. mysticus, Gr. ?
   belonging to secret rites, from ? one initiated: cf. F.
   mystique. See 1st {Mystery}, {Misty}.]
   1. Remote from or beyond human comprehension; baffling human
      understanding; unknowable; obscure; mysterious.
   
            Heaven's numerous hierarchy span The mystic gulf
            from God to man.                      --Emerson.
   
            God hath revealed a way mystical and supernatural.
                                                  --Hooker.
   
   2. Importing or implying mysticism; involving some secret
      meaning; allegorical; emblematical; as, a mystic dance;
      mystic Babylon.
   
            Thus, then, did the spirit of unity and meekness
            inspire every joint and sinew of the mystical body.
                                                  --Milton.
      -- {Mys"tic*al*ly}, adv. -- {Mys"tic*al*ness}, n.
   
   

2. \Mys"tic\, n.
   One given to mysticism; one who holds mystical views,
   interpretations, etc.; especially, in ecclesiastical history,
   one who professed mysticism. See {Mysticism}.
   
   

An early system on the ibm 704, ibm 650, ibm 1103 and 1103A.

[Listed in CACM 2(5):16 (May 1959)].