expression n.

late 14c., "represent in visual arts; put into words," from Old French espresser, expresser "press, squeeze out; speak one's mind" (Modern French exprimer), Medieval Latin expressare, frequentative of Latin exprimere "represent, describe, portray, imitate, translate," literally "to press out" (source also of Italian espresso); the sense evolution here perhaps is via an intermediary sense such as "clay, etc., that under pressure takes the form of an image," from ex "out" (see ex-) + pressare "to press, push," from Latin premere "to press, hold fast, cover, crowd, compress" (from PIE root *per- (4) "to strike"). Related: Expressed; expresses; expressing; expressible.

1850 in reference to an artist who seeks to portray the emotional experience of the subject, from expression (which was used in the fine arts by 1715 with a sense "way of expressing") + -ist. Modern sense is from 1914, from expressionism (from 1908 as an artistic style or movement). As a noun from 1880. Related: Expressionistic.

1831, "giving no expression," from expression + -less. Shelley used it with a sense of "unexpressed" (1819).