cankerEnglishOxford American Thesauruscanker noun 1 a plant which is very susceptible to canker: fungal disease, fungal rot, plant rot; blight. 2 ear cankers in rabbits are caused by a mite: ulcer, ulceration, infection, sore, running sore, lesion, abscess, chancre. 3 racism remains a canker at the heart of the nation: blight, evil, scourge, poison, cancer, sickness, disease, pestilence, plague; rot, corruption.