languor (n.) Look up languor at Dictionary.com
c.1300, "disease, distress, mental suffering," from Old French langor "sickness, weakness" (Modern French langueur), from Latin languorem (nominative languor) "faintness, feebleness, lassitude," from languere "be weak or faint" (see lax). Sense shifted to "faintness, weariness" (1650s) and "habitual want of energy" (1825).