9 letters · 14 points in Scrabble
verb have sex without being married
originFirst attested in 1552; borrowed from Latin fornicātus, perfect active participle of fornicor (see -ate (verb-forming suffix)), from fornix (“arch, vault; brothel”). It was customary for courtesans of the era to wait for their customers out of the rain in arched passageways.
Etymology from Wiktionary, CC BY-SA 3.0