quirk Definition

quirk
noun

1. An odd habit, mannerism or aspect of personality, etc.

Thesaurus: idiosyncrasy, mannerism, peculiarity, eccentricity, peccadillo, foible, caprice, vagary, fetish, oddity, turn.
2. An odd twist in affairs or turn of events; a strange coincidence.
3. archit.
A sharp-angled groove or hollow in a moulding.

Derivative: quirkish
adj

Derivative: quirkiness
noun

Etymology: 16c.