Yours, Etc.: Origins and Uses of 8 Sign-Offs
c.1200, from Old French lecherie "impertinence, deceit," from lecheor (see lecher).
The priests had excellent cause to forbid us lechery: this injunction, by reserving to them acquaintance with and absolution for these private sins, gave them an incredible ascendancy over women, and opened up to them a career of lubricity whose scope knew no limits. [Marquis de Sade, "Philosophy in the Bedroom"]