Webster's Revised Unabridged Dictionary · 1913

Vitiate

Vitiate , transitive verb

[Latin vitiatus, p. p. vitiare to vitiate, from vitium a fault, vice. See Vice a fault.]

1.
To make vicious, faulty, or imperfect; to render defective; to injure the substance or qualities of; to impair; to contaminate; to spoil; as, exaggeration vitiates a style of writing; sewer gas vitiates the air.
A will vitiated and growth out of love with the truth disposes the understanding to error and delusion. — South
Without care it may be used to vitiate our minds. — Burke
This undistinguishing complaisance will vitiate the taste of readers. — Garth
2.
To cause to fail of effect, either wholly or in part; to make void; to destroy, as the validity or binding force of an instrument or transaction; to annul; as, any undue influence exerted on a jury vitiates their verdict; fraud vitiates a contract.