mannerism

Concise Oxford English Dictionary © 2008 Oxford University Press:
mannerism/ˈmanərɪzəm/

▶noun

• 1 a habitual gesture or way of speaking or behaving.

• 2 excessive or self-conscious use of a distinctive style in art, literature, or music.

• 3 (Mannerism) a style of 16th-century Italian art characterized by distortions in scale and perspective and the use of bright, often lurid colours.

– derivatives
mannerist noun & adjective,
manneristic adjective.