mysterious

adjective4

1. •
   so strange that nobody can easily explain it or make sense of it

   • Why he left without saying goodbye is quite mysterious.
2. •
   Of unknown origin.

   • He received a mysterious phone call this morning.
3. •
   Having unknown qualities.

   • Our boss is a mysterious man who hardly ever meets with us.
4. •
   Deliberately evasive or enigmatic.

   • Stop being mysterious and just tell me what you want.