Merriam-Webster Collegiate Dictionary - lust

 I. noun  Etymology: Middle English, from Old English; akin to Old High German ~ pleasure and perhaps to Latin lascivus wanton  Date: before 12th century  1. obsolete  a. pleasure, delight  b. personal inclination ; wish  2. usually intense or unbridled sexual desire ; lasciviousness  3.  a. an intense longing ; craving a ~ to succeed  b. enthusiasm, eagerness admired his ~ for life  II. intransitive verb  Date: 12th century to have an intense desire or need ; crave; specifically to have a sexual urge