vitiation

verb (used with object), vi·ti·at·ed, vi·ti·at·ing.

1. to impair the quality of; make faulty; spoil.
2. to impair or weaken the effectiveness of.
3. to debase; corrupt; pervert.
4. to make legally defective or invalid; invalidate: to vitiate a claim.

verb (tr)

1. to make faulty or imperfect
2. to debase, pervert, or corrupt
3. to destroy the force or legal effect of (a deed, etc)to vitiate a contract

v.

1530s, from Latin vitiatus, past participle of vitiare “to make faulty, injure, spoil, corrupt,” from vitium “fault, defect, blemish, crime, vice” (see vice (n.1)). Related: Vitiated; vitiating.

n.

1. A change in a process that impairs utility or reduces efficiency.