early 15c., dissipacioun, "disintegration, dissolution," from Latin dissipationem (nominative dissipatio) "a scattering," noun of action from past-participle stem of dissipare "to spread abroad, scatter, disperse; squander, disintegrate" (see dissipate). Sense of "act of wasting by misuse, wasteful expenditure or consumption" is from 1630s; meaning "intemperate mode of living, undue indulgence in pleasure" is from 1784.
Classicism criticises; romanticism creates. Classicism enjoins self-control; romanticism encourages self-indulgence. Classicism is mold; romanticism is matter. Classicism is art; romanticism is nature. Classicism is law; romanticism is life. Romanticism is undoubtedly first and indispensable; but so, not less, classicism is indispensable, though second. [William C. Wilkinson, "Classic French Course in English," 1890]
"a going beyond ordinary, necessary, or proper limits; superfluity; undue indulgence of appetite, want of restraint in gratifying the desires; the amount by which one number or quantity exceeds another," late 14c., from Old French exces (14c.) "excess, extravagance, outrage," from Latin excessus "departure, a going beyond the bounds of reason or beyond the subject," from stem of excedere "to depart, go beyond," from ex "out" (see ex-) + cedere "to go, yield" (from PIE root *ked- "to go, yield"). As an adjective, "beyond what is necessary, proper, or right," from late 15c.
From late 14c. as "lightheartedness, cheerfulness." A word with more senses in Middle and early Modern English than recently: "sexual pleasure or indulgence, lust" (mid-14c.); "insolent presumptuousness, impudence" (mid-14c.); "vigor, strength" (mid-14c.); "love; a love affair" (c. 1300, hence in jollity "by fornication, out of wedlock"); "gallantry" (1530s); "state of splendor" (1540s).
late 14c., rigour, "harshness, severity in dealing with persons; force; cruelty," from Old French rigor "strength, hardness" (13c., Modern French rigueur), from Latin rigorem (nominative rigor) "numbness, stiffness, hardness, firmness; roughness, rudeness," from rigēre "be stiff" (from PIE root *reig- "stretch; be stretched; be stiff").
Also, in medieval medicine, "a sudden chill" (c. 1400). From early 15c. as "exactness, strictness without indulgence" (of discipline, the law, etc.). Compare rigidity. Rigorism "rigidity in principles or practice" (originally religious) is from 1704. Rigidist is by 1716.
"belief in more gods than one," 1610s, from French polythéisme (16c.), formed from Greek polytheia "polytheism," polytheos "of or belonging to many gods," from polys "many" (from PIE root *pele- (1) "to fill") + theos "god" (from PIE root *dhes-, forming words for religious concepts).
The various modes of worship, which prevailed in the Roman world, were all considered by the people, as equally true; by the philosopher, as equally false; and by the magistrate, as equally useful. And thus toleration produced not only mutual indulgence, but even religious concord. [Gibbon]
The doctrine of Aristippus and the Cyrenaic school of Greek philosophers, that the pleasure of the moment is the only possible end, that one kind of pleasure is not to be preferred to another, and that a man should in the interest of pleasure govern his pleasures and not be governed by them; hence, that ethical doctrine which regards pleasure or happiness as the highest good. ... Egoistic hedonism considers only the pleasure of the individual; altruistic hedonism takes into account that of others. [Century Dictionary]