early 13c., "joyful, merry;" late 14c., "full of healthy vigor," from lust (n.) + -y (2). Used of handsome dress, fine weather, good food, pleasing language, it largely escaped the Christianization and denigration of the noun in English. The sense of "full of desire" is attested from c. 1400 but seems to have remained secondary. Related: Lustily; lustiness.
