c.1175, from O.Fr.
lecheor "one living a life of debauchery," esp. "one given to sexual indulgence," lit. "licker," agent noun from
lechier "to lick, to live in debauchery or gluttony," from Frank.
*likkon, from P.Gmc.
*likkojan "to lick" (see
lick). Noun
lech "strong desire" is a 1796 back-formation.
"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]
[lech-er] 
ər