Mysterious (adjective)

Having an aura of mystery or a puzzling, unclear quality.

Origin:

Late middle english: from old french mystere, from latin mystērium "a secret, mystery", from greek mustērion.

Examples:

1. She had a mysterious smile on her face.
2. The island was surrounded by a mysterious mist.
3. The story had a mysterious ending.
4. The man was known for his mysterious behavior.
5. The painting had a mysterious aura that captivated the onlookers.