vitiate

[vish-ee-eyt] /ˈvɪʃ iˌeɪt/
verb (used with object), vitiated, vitiating.
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.
Origin
1525-35; < Latin vitiātus, past participle of vitiāre to spoil, derivative of vitium blemish, vice1 + -ātus -ate1
Related forms
vitiation, noun
vitiator, noun
nonvitiation, noun
unvitiated, adjective
unvitiating, adjective
Can be confused
ameliorate, obviate, vitiate.
British Dictionary definitions for vitiate

vitiate

/ˈvɪʃɪˌeɪt/
verb (transitive)
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
Derived Forms
vitiable, adjective
vitiation, noun
vitiator, noun
Word Origin
C16: from Latin vitiāre to injure, from vitium a fault
Word Origin and History for vitiate
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.