MILDEW

I. noun Etymology: Middle English, from Old English meledēaw honeydew; akin to Old High German militou honeydew Date: 14th century 1. a superficial usually whitish growth produced especially on organic matter or living plants by fungi (as of the families Erysiphaceae and Peronosporaceae), a fungus producing ~, a discoloration caused by fungi, ~y adjective II. verb Date: 1606 transitive verb to affect with or as if with ~, intransitive verb to become affected with ~