Lewd
Old English lǣwede, of unknown origin. The original sense was ‘belonging to the laity’; in Middle English, ‘belonging to the common people, vulgar’, and later ‘worthless, vile, evil’, leading to the current sense.
wiktionary
From Middle English lewed, lewd, leued(“unlearned, lay, lascivious”), from Old English lǣwede(“unlearned, ignorant, lay”), of obscure origin; most likely a derivative of the past participle of lǣwan(“to reveal, betray”) in the sense of "exposed as being unlearned" or "easily betrayed, clueless", from Proto-Germanic *lēwijaną(“to betray”), from *lēwą(“an opportunity, cause”), from Proto-Indo-European *lēw-(“to leave”). Or, according to the OED, from Vulgar Latin *laigo-, from Late Latin laicus(“of the people”).
Cognate with Old High German gilāen, firlāen(“to betray”), Gothic 𐌲𐌰𐌻𐌴𐍅𐌾𐌰𐌽( galēwjan, “to give over, betray”), Gothic 𐌻𐌴𐍅( lēw, “an opportunity, cause”).
lewd (third-person singular simple present lewds, present participle lewding, simple past and past participle lewded)
etymonline
lewd (adj.)
Middle English leued, from Old English læwede "nonclerical, unlearned," of uncertain origin but according to OED probably ultimately from Vulgar Latin *laigo-, from Late Latin laicus "belonging to the people" (see lay (adj.)).
Sense of "unlettered, uneducated" (early 13c.) descended to "coarse, vile, lustful" by late 14c. In Middle English often paired alliteratively with learned. It also was a noun in Old English, "layman;" for nouns, Elizabethan English made lewdster, lewdsby. Related: Lewdly; lewdness.
