1 (of envy, disappointment, etc., or their cause) cause persistent annoyance or resentment.
2 archaic (of a wound, sore, etc.) fester, continue to be painful.
Etymology: ME (in sense 2) f. OF rancler f. rancle, draoncle festering sore f. med.L dranculus, dracunculus dimin. of draco serpent
Useful english dictionary. 2012.