concupiscence \kon-KYOO-puh-suhn(t)s; kuhn-\ (noun) - Strong desire, especially sexual desire; lust.
"Now, to speak of the first desire, that is, concupiscence, accordint to the law for our sexual parts, which were lawfully made and by rightful word of God; I say, for as much as man is not obedient to God, Who is his Lord, therefore is the flesh disobedient to Him, through concupiscence, wich is also called the nourishing of and the reason for sin." -- Geoffrey Chaucer, 'The Canterbury Tales'
Concupiscence is from Late Latin concupiscentia, from the present participle of Latin concupiscere, "to desire eagerly," from com-, intensive prefix + cupere, "to desire." The adjective form is concupiscent. The name of the ancient Roman god of love, Cupid, comes from the same root.