1660s, "posture or position of a figure in a statue or painting," via French attitude (17c.), from Italian attitudine "disposition, posture," also "aptness, promptitude," from Late Latin aptitudinem (nominative aptitudo; see aptitude, which is its doublet).
Originally 17c. a technical term in art; later generalized to "a posture of the body supposed to imply some mental state" (1725). Sense of "a settled behavior reflecting feeling or opinion" is by 1837. Meaning "habitual mode of regarding" is short for attitude of mind (1757). Connotations of "antagonistic and uncooperative" developed by 1962 in slang.
Attitude is generally studied for the sake of looking graceful ; hence it is sometimes affected, the practice of it being then called attitudinizing. An attitude is often taken intentionally for the purpose of imitation or exemplification ; generally attitude is more artistic than posture. [Century Dictionary]
"act of posing the body; attitude, position, whether taken naturally or assumed for effect," 1818, from pose (v.1), in a sense developed in the French cognate. Figuratively, "attitude of mind or conduct," from 1884. Earlier in English it meant "something deposited, a pledge" (mid-15c., from Old French pose, past participle of poser), hence "a secret hoard or treasure."
"one who practices an affected attitude," 1881, agent noun from pose (v.1); revived in teenager slang by 1983.
figurative for a puritan attitude toward the arts at least since Shaw (1916), from the name of Girolamo Savonarola (1452-1498), Dominican monk famous for his fierce opposition to moral licence and Church corruption.