Definition of canker
noun
1a necrotic, fungal disease of apple and other trees that results in damage to the bark. an open lesion in plant tissue caused by infection or injury. fungal rot in some fruits and vegetables, e.g., parsnips and tomatoes.
2 Medicine an ulcerous condition or disease, in particular. (also
canker sore)
a small ulcer of the mouth or lips. ulceration of the throat and other orifices of birds, typically caused by a protozoal infection. (also ear canker) inflammation of the ear of a dog, cat, or rabbit, typically caused by a mite infestation. a malign and corrupting influence that is difficult to eradicate: [in singular]:racism remains a canker at the heart of the nation
verb
1 [no object] (of woody plant tissue) become infected with canker: (as noun cankering)we found some cankering of the wood
2 [with object] (usually as adjective
cankered)
infect with a pervasive and corrupting bitterness:he hated her with a cankered, shameful abhorrence