Enigmatic (adjective)

Difficult to understand or interpret; mysterious.

Origin:

Early 17th century: from greek ainigmatikos, from ainigma "riddle".

Examples:

1. His enigmatic smile made people curious.
2. Her enigmatic behavior made people wonder.
3. The painting was enigmatic and open to interpretation.
4. The statement was enigmatic and left people confused.
5. The message was enigmatic and needed to be deciphered.