n. An ulcer; a rankling sore; a small purulent tumor; more particularly, a superficial suppuration resulting from irritation of the skin, the pus being developed in vesicles of irregular figure and extent.n. The act of festering or rankling.To become a fester; generate purulent matter, as a wound; suppurate; ulcerate.To become corrupt; generate rottenness; rot.To become more and more virulent; rankle, as a feeling of resentment or hatred.To cause to fester: as, exposure festers a wound.To cause to rankle, as a feeling of resentment.n. Same as festue.