Nouns

(n)cankera fungal disease of woody plants that causes localized damage to the bark
(n)canker, canker sorean ulceration (especially of the lips or lining of the mouth)
(n)pestilence, cankera pernicious and malign influence that is hard to get rid of“racism is a pestilence at the heart of the nation”, “according to him, I was the canker in their midst”

Verbs

(v)cankerbecome infected with a canker
(v)cankerinfect with a canker