Mystic, Mystical, a.
Etymology: [L. mysticus, Gr. 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.
Shades of meaning
Fernald has no entry of its own for mystical; he lists it under mysterious.
Where he writes about it:
That is mystic or mystical which has associated with it some hidden or recondite meaning, especially of a religious kind; as, the mystic Babylon of the Apocalypse. — from mysterious