vitiation

from WordNet (r) 3.0 (2006)

vitiation
    n 1: nullification by the destruction of the legal force;
         rendering null; "the vitiation of the contract"

from The Collaborative International Dictionary of English v.0.48

Vitiation \Vi`ti*a"tion\, n. [L. vitiatio.]
   The act of vitiating, or the state of being vitiated;
   depravation; corruption; invalidation; as, the vitiation of
   the blood; the vitiation of a contract.
   [1913 Webster]

         The vitiation that breeds evil acts.     --G. Eliot.
   [1913 Webster]