From Middle English lechour, from Old French lecheor (“glutton, sensualist, libertine”) , from Old French lecher, lechier, lekier, lescher (“to lick, live in gluttony or sensuality”), from Old Frankish *likkōn (“to lick”), from Proto-Germanic *likkōną (“to lick”), from Proto-Indo-European *leyǵʰ- (“to lick”). More at lick.