The Collaborative International Dictionary of English v.0.48:

Cankered \Can"kered\, a.
   1. Affected with canker; as, a cankered mouth.
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   2. Affected mentally or morally as with canker; sore,
      envenomed; malignant; fretful; ill-natured. "A cankered
      grandam's will." --Shak.
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The Collaborative International Dictionary of English v.0.48:

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.
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            No lapse of moons can canker Love.    --Tennyson.
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   2. To infect or pollute; to corrupt. --Addison.
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            A tithe purloined cankers the whole estate.
                                                  --Herbert.
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