Piquant

Definitions: (1) exciting curiosity; mentally stimulating; provoking interest; (2) agreeably stimulating to the taste; pleasantly sharp or biting

Synonyms: charming, clever, lively, smart, spirited

Comment: This quality most often references spicy food, but it is used here as a way of thinking about human traits. We can imagine a person who can spice up a conversation, has a sharp (but not acerbic) wit, or encourages interest in exciting topics.