Is it ensure, insure, or assure?
Old English læwede "nonclerical," of uncertain origin but probably ultimately from Vulgar Latin *laigo-, from Latin laicus (see lay (adj.)). Sense of "unlettered, uneducated" (early 13c.) descended to "coarse, vile, lustful" by late 14c. Related: Lewdly; lewdness.
(Acts 18:14), villany or wickedness, not lewdness in the modern sense of the word. The word "lewd" is from the Saxon, and means properly "ignorant," "unlearned," and hence low, vicious (Acts 17:5).