a habitual or characteristic manner, mode, or way of doing something; distinctive quality or style, as in behavior or speech:
He has an annoying mannerism of tapping his fingers while he talks. They copied his literary mannerisms but always lacked his ebullience.
marked or excessive adherence to an unusual or a particular manner, especially if affected:
Natural courtesy is a world apart from snobbish mannerism.
(usually initial capital letter) a style in the fine arts developed principally in Europe during the 16th century, chiefly characterized by a complex perspectival system, elongation of forms, strained gestures or poses of figures, and intense, often strident color.
British Dictionary definitions for manneristically
a distinctive and individual gesture or trait; idiosyncrasy
(often capital) a principally Italian movement in art and architecture between the High Renaissance and Baroque periods (1520–1600) that sought to represent an ideal of beauty rather than natural images of it, using characteristic distortion and exaggeration of human proportions, perspective, etc
adherence to a distinctive or affected manner, esp in art or literature