n. & v.
n. 1 a a destructive fungus disease of trees and plants. b an open wound in the stem of a tree or plant. 2 Zool. an ulcerous ear disease of animals esp. cats and dogs. 3 Med. an ulceration esp. of the lips. 4 a corrupting influence.
v.tr. 1 consume with canker. 2 corrupt. 3 (as cankered adj.) soured, malignant, crabbed. canker-worm any caterpillar of various wingless moths which consume the buds and leaves of shade and fruit trees in n. America. cankerous adj.
[ OE cancer & ONF cancre, OF chancre f. L cancer crab ]