adjective.
Of or resembling an enigma; puzzling: synonym: mysterious.
The Century Dictionary and Cyclopedia
Relating to or containing an enigma; obscure; darkly expressed or indicated; ambiguous.
Synonyms Mysterious, puzzling, dark, recondite.
the GNU version of the Collaborative International Dictionary of English
adjective.
Relating to or resembling an enigma; not easily explained or accounted for; darkly expressed; not clear to the understanding; obscure; puzzling.