Mysterious, a.
Etymology: [F. mystèrieux. See 1st Mystery.]
Of or pertaining to mystery; containing a mystery; difficult or impossible to understand; obscure not revealed or explained; enigmatical; incomprehensible. God at last To Satan, first in sin, his doom applied, Thought in mysterious terms. Milton.
Syn. -- Obscure; secret; occult; dark; mystic; cabalistic; enigmatical; unintelligible; incomprehensible.
Shades of meaning
That is mysterious in the true sense which is beyond human comprehension, as the decrees of God or the origin of life. 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. That is dark which we can not personally see through, especially if sadly perplexing; as, a dark providence. That is secret which is intentionally hidden. Compare dark.