This word means more than just "want to know/learn." It generally implies some kind of active interest in the topic or an underlying motivation for wanting to know something about it. The word cannot be used to mean "strange."

tlhIngan Hol rer ("He/she is curious about Klingon")

rer tlhIngan ("The Klingon is curious" - about a previously stated topic or just a statement about the Klingon's nature)

This verb cannot be used adjectivally.