D defs.my
Entry 1 sense Webster, 1913

Mysterious

/mĭs-tĭr'-ē-əs/ · Mys·te·ri·ous · IPA /mɪˈstɪɹi.əs/
01 a. Of or pertaining to mystery; containing a mystery; difficult or impossible to understand; inexplicable; obscure; not revealed or explained;…
  1. 1.
    Of or pertaining to mystery; containing a mystery; difficult or impossible to understand; inexplicable; obscure; not revealed or explained; enigmatical; incomprehensible.
    “God at last To Satan, first in sin, his doom applied, Thought in mysterious terms.” Milton.