Canker \Can"ker\ (k[a^][ng]"k[~e]r), n. [OE. canker, cancre, AS. cancer (akin to D. kanker, OHG chanchar.), fr. L. cancer a cancer; or if a native word, cf. Gr. ? excrescence on tree, ? gangrene. Cf. also OF. cancre, F. chancere, fr. L. cancer. See cancer, and cf. Chancre.]

1. A corroding or sloughing ulcer; esp. a spreading gangrenous ulcer or collection of ulcers in or about the mouth; -- called also water canker, canker of the mouth, and noma.

2. Anything which corrodes, corrupts, or destroy.

The cankers of envy and faction. --Temple.

3. (Hort.) A disease incident to trees, causing the bark to rot and fall off.

4. (Far.) An obstinate and often incurable disease of a horse's foot, characterized by separation of the horny portion and the development of fungoid growths; -- usually resulting from neglected thrush.

5. A kind of wild, worthless rose; the dog-rose.

To put down Richard, that sweet lovely rose. And plant this thorm, this canker, Bolingbroke. --Shak.

Black canker. See under Black.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Canker \Can"ker\ (k[a^][ng]"k[~e]r), v. t. [imp. & p. p. Cankered (-k[~e]rd); p. pr. & vb. n. Cankering.]

1. To affect as a canker; to eat away; to corrode; to consume.

No lapse of moons can canker Love. --Tennyson.

2. To infect or pollute; to corrupt. --Addison.

A tithe purloined cankers the whole estate. --Herbert.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Canker \Can"ker\, v. i.

1. To waste away, grow rusty, or be oxidized, as a mineral. [Obs.]

Silvering will sully and canker more than gliding. --Bacom.

2. To be or become diseased, or as if diseased, with canker; to grow corrupt; to become venomous.

Deceit and cankered malice. --Dryden.

As with age his body uglier grows, So his mind cankers. --Shak.

Source: Webster's Revised Unabridged Dictionary (1913)