Can"ker (kă?"kẽr), 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.

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.

Black canker. See under Black.

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.

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

Deceit and cankered malice.

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

Can"ker (kă?"kẽr), v. t. [imp. & p. p. Cankered (- kẽrd); 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.

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

A tithe purloined cankers the whole estate.