Origin and history of leprous

"one afflicted with leprosy," late 14c., earlier "the disease leprosy," from Late Latin lepra, from Greek lepra "leprosy," noun use of fem. of lepros (adj.) "scaly, scabby, rough, leprous," related to lepein "to peel," from lepos, lepis "a scale," from PIE root *lep- (1) "to peel," which also yields words for "something delicate and weak," via the notion of "small shaving, flake, scale" (cognates: Latin lepidus "pleasant, charming, fine, elegant, effeminate," lepos "pleasantness, agreeableness;" Old English læfer "rush, reed; metal plate;" Lithuanian lopas "patch, rag, cloth," lepus "soft, weak, effeminate").

Originally in Middle English this was the word for the disease itself (mid-13c., via Old French lepre); the shift in meaning to "person with leprosy" perhaps developed in Anglo-French, or is because the -er ending resembled an agent-noun affix. By mid-15c. other nouns for the disease were being coined (see leprosy). In English lepra also was an old name for psoriasis (late 14c.).

name given to various chronic skin diseases, later in more restricted use, 1530s, probably from leprous + -y (4). First used in Coverdale Bible, where it renders Hebrew cara'ath, which apparently was a comprehensive term for skin diseases. Also known as Hansen's disease (1938) for Norwegian physician Gerhard Henrik Armauer Hansen (1841-1912) who in 1871 discovered the bacillus that causes it.

The Middle English name for the disease was leper (mid-13c.), from Old French liepre and Latin lepra (see leper). But as the sense of this shifted after late 14c. to mean "person with leprosy," English began coining new nouns for the disease: lepri, leprosity, lepruse all date from mid-15c. but are now obsolete. A place for their treatment is a leprosarium (1846) or leprosary (1869, from French).