*au-

"person of advanced and fine artistic sensibilities," attested from 1878, in vogue 1881, from Greek aisthētēs "one who perceives," from stem of aisthanesthai "to perceive (by the senses or by the mind), to feel," from PIE *awis-dh-yo-, from root *au- "to perceive." Or perhaps it is from aesthetic on the model of athlete/athletic. The idea is somewhat older than the word. Aesthetician "professor of taste" is from 1829; aestheticist is from 1868.

1. Properly, one who cultivates the sense of the beautiful; one in whom the artistic sense or faculty is highly developed; one very sensible of the beauties of nature or art.—2. Commonly, a person who affects great love of art, music, poetry, and the like, and corresponding indifference to practical matters; one who carries the cultivation of subordinate forms of the beautiful to an exaggerated extent: used in slight contempt. [Century Dictionary, 1897]

I want to be an aesthete,

  And with the aesthetes stand;

A sunflower on my forehead,

  And a lily in my hand.

[Puck, Oct. 5, 1881]

1798, from German Ästhetisch (mid-18c.) or French esthétique (which is from German), ultimately from Greek aisthetikos "of or for perception by the senses, perceptive," of things, "perceptible," from aisthanesthai "to perceive (by the senses or by the mind), to feel," from PIE *awis-dh-yo-, from root *au- "to perceive."

Popularized in English by translations of Kant and used originally in the classically correct sense "science which treats of the conditions of sensuous perception" [OED]. Kant had tried to reclaim the word after Alexander Baumgarten had taken it in German to mean "criticism of taste" (1750s), but Baumgarten's sense attained popularity in English c. 1830s (despite scholarly resistance) and freed the word from philosophy.

Walter Pater used it (1868) to describe the late 19c. movement that advocated "art for art's sake," which further blurred the sense. [Whewell had proposed callesthetics for "the science of the perception of the beautiful."]

As an adjective by 1798 "of or pertaining to sensual perception;" 1821 as "of or pertaining to appreciation of the beautiful." Related: Aesthetically.