10 letters · 15 points in Scrabble
adjective socially incorrect in behavior
originFrom Middle English unmanerli (“of a person: disorderly, unruly; of conduct: inappropriate, improper”), from un- (prefix meaning ‘not’) + manerli, manerly (“well-mannered; modest; customary; moral”). Manerli is derived from maner (“kind, sort; form, nature; circumstances; method, manner; outward behaviour, manners; morals; custom, usage; cause, reason”) (from Anglo-Norman, Old French manere…
Etymology from Wiktionary, CC BY-SA 3.0