"external behavior (especially polite behavior) in social intercourse," late 14c., plural of manner in a specific sense of "proper behavior, commendable habits of conduct" (c. 1300).

Under bad manners, as under graver faults, lies very commonly an overestimate of our special individuality, as distinguished from our generic humanity. [Oliver W. Holmes, "The Professor at the Breakfast Table," 1858]

Earlier it meant "moral character" (early 13c.).

MANNERS-BIT, a portion of a dish left by the guests that the host may not feel himself reproached for insufficient preparation. [Rev. Joseph Hunter, "The Hallamshire Glossary," 1829]

1530s "gloomy, of a sour temper, sullen and austere," from Latin morosus "morose, peevish, hypercritical, fastidious," from mos (genitive moris) "habit, custom" (see moral (adj.)). In English, manners by itself means "(good) manners," but here the implication in Latin is "(bad) manners."

late 14c., "want of cultivation or manners, uncouthness;" c. 1400, "plainness, lack of artistry," from rude (adj.) + -ness. From 1530s, "bad manners." Rudeship (mid-15c.) also was used in the sense of "lack of gentleness, roughness."

"rich person of vulgar manners," 1804, from vulgar (adj.) + -ian.

1550s, "incivility, bad manners, rudeness;" see dis- "opposite of" + courtesy. Perhaps based on Old French discourtoisie (15c.), from discourtois. Meaning "an act of disrespect" is from 1590s.

"proper style and manners in communicating on the internet," 1993, coined punningly from net, short for internet + etiquette.

"seemly, modest," late 14c. (a sense now obsolete); "well-mannered, polite, showing good manners," 1520s; from manner (n.) + -ly (1). As an adverb, "in accord with custom; becomingly" (mid-14c.); later "in accord with good manners" (c. 1400). Related: Mannerliness.

late 14c., "moral, virtuous," from well (adv.) + mannered. Meaning "with good manners" is from 1540s.

"customs," 1907 (W.G. Sumner, "Folkways"), from Latin mores "customs, manners, morals" (see moral (adj.)).

1580s, "function or manners of a stage clown or jester," from clown (n.) + -age. From 1630s as "actions or behavior of a rustic."