lecher:  Etymologically, a lecher is a ‘licker’. English borrowed the word from Old French lecheor, a derivative of the verb lechier ‘lick’, which was used figuratively for ‘live a life of debauchery’. This in turn came from Frankish *likkōn, a descendant of the same prehistoric Germanic source as English lick [OE]. The inspiration of the metaphor, which originally encompassed the pleasures of the table as well as of the bed, was presumably the tongue as an organ of sensual gratification. => lick
"man given to excessive sexual indulgence," late 12c., from Old French lecheor (Modern French lécheur) "one living a life of debauchery," especially "one given to sexual indulgence," literally "licker," agent noun from lechier "to lick, to live in debauchery or gluttony," from Frankish *likkon or some other Germanic source, from Proto-Germanic *likkojan "to lick" or some other Germanic source (see lick). The Old French feminine form was lechiere. Middle English, meanwhile, had lickestre "female who licks;" figuratively "a pleasure seeker," literally "lickster."