gangrene (n.)

"putrefaction or necrosis of soft tissues," 1540s, cancrena, from Latin gangraena (Medieval Latin cancrena), from medical Greek gangraina "an eating or gnawing sore," literally "that which eats away," a dissimilated, reduplicated form of gran- "to gnaw," from PIE root *gras- "to devour" (see gastric).