Interest in a third person or disloyalty toward a spouse; also refers to a lack of loyalty toward one's own group or organization.

The center of the circumscribed circle of a triangle or other polygon.

(literary) Disloyal or rebellious disposition, especially of a minister toward a ruler; (archaic) an inclination to collude with a foreign power.

(literary) The act of focusing one's attention on external appearances or superficial etiquette rather than sincerity.