rankle

The history of today's word is something of a sore subject. When rankle was first used in English, it meant "to fester," and that meaning is linked to the word's Old French ancestor—the noun raoncle or draoncle, which meant "festering sore." Etymologists think this Old French word was derived from the Latin dracunculus, a diminutive form of draco, which means "serpent" and which is the source of the English word dragon. The transition from serpents to sores apparently occurred because people thought certain ulcers or tumors looked like small serpents.