mysterious

adj

1. Of unknown origin.

   “He received a mysterious phone call this morning.”

2. Having unknown qualities.

   “Our boss is a mysterious man who hardly ever meets with us.”

   “God moves in a myſterious way, / His wonders to perform; / He plants his footſteps in the ſea, / And rides upon the ſtorm.”

3. Difficult to understand.

   “Why he left without saying goodbye is quite mysterious.”

   “Buttressed by clothes, walls and objects, there was the bourgeois family, the most mysterious institution of the age.”

4. Deliberately evasive or enigmatic.

   “Stop being mysterious and just tell me what you want.”