art brut n.

early 13c., "skill as a result of learning or practice," from Old French art (10c.), from Latin artem (nominative ars) "work of art; practical skill; a business, craft," from PIE *ar(ə)-ti- (source also of Sanskrit rtih "manner, mode;" Greek artizein "to prepare"), suffixed form of root *ar- "to fit together." Etymologically akin to Latin arma "weapons" (see arm (n.2)).

In Middle English usually with a sense of "skill in scholarship and learning" (c. 1300), especially in the seven sciences, or liberal arts. This sense remains in Bachelor of Arts, etc. The meaning "human workmanship" (as opposed to nature) is from late 14c. The meaning "system of rules and traditions for performing certain actions" is from late 15c. The sense of "skill in cunning and trickery" is attested by late 16c. (the sense in artful, artless). The meaning "skill in creative arts" is recorded by 1610s; especially of painting, sculpture, etc., from 1660s.

In science you must not talk before you know. In art you must not talk before you do. In literature you must not talk before you think. [Ruskin, "The Eagle's Nest," 1872]

Supreme art is a traditional statement of certain heroic and religious truths, passed on from age to age, modified by individual genius, but never abandoned. The revolt of individualism came because the tradition had become degraded, or rather because a spurious copy had been accepted in its stead. [William Butler Yeats, journal, 1909]

Expression art for art's sake (1824) translates French l'art pour l'art. First record of art critic is from 1847. Arts and crafts "decorative design and handcraft" is from the Arts and Crafts Exhibition Society, founded in London in 1888.

early 15c., "of or belonging to animals, non-human," from Old French brut "coarse, brutal, raw, crude," from Latin brutus "heavy, dull, stupid, insensible, unreasonable" (source also of Spanish and Italian bruto), said to be an Oscan word, from PIE *gwruto-, suffixed form of root *gwere- (1) "heavy" (see de Vaan).

Before reaching English the meaning expanded to "of the lower animals." Used in English of human beings from 1530s, "wanting in reason, blunt or dull of sentiment, unintelligent." The sense in brute force (1736) is "irrational, purely material."

Brute ... remains nearest to the distinguishing difference between man and beast, irrationality .... Brutish is especially uncultured, stupid, groveling .... Brutal implies cruelty or lack of feeling: as brutal language or conduct. [Century Dictionary]