decorative (adj.)
early 15c., "beautifying, made to remove or cover up blemishes," from Old French decoratif and directly from decorat-, past-participle stem of Latin decorare "to decorate, adorn, embellish, beautify," from decus (genitive decoris) "an ornament; grace, dignity, honor," from PIE root dek- "to take, accept" (on the notion of "to add grace"). From 1791 as "of or pertaining to decoration, of an ornamental nature."
art (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."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. Meaning "human workmanship" (as opposed to nature) is from late 14c. Meaning "system of rules and traditions for performing certain actions" is from late 15c. Sense of "skill in cunning and trickery" first attested late 16c. (the sense in artful, artless). Meaning "skill in creative arts" is first recorded 1610s; especially of painting, sculpture, etc., from 1660s.