Why is the ninth month called September?
"one afflicted with leprosy," late 14c., from Late Latin lepra, from Greek lepra "leprosy," from fem. of lepros (adj.) "scaly," from leops "a scale," related to lepein "to peel," from lopos "a peel," from PIE root *lep- "to peel, scale" (see leaf (n.)). Originally the word for the disease itself (mid-13c.); because of the -er ending it came to mean "person with leprosy," so leprosy was coined 16c. from adjective leprous.
leper lep·er (lěp'ər)
One who has leprosy.