Verb

(vitiat)

to spoil, make faulty; to reduce the value, quality, or effectiveness of something

*1851 ,

There was excellent blood in his veins—royal stuff; though sadly vitiated , I fear, by the cannibal propensity he nourished in his untutored youth.

* 1997': ‘Mr Rose,’ says the Physician, ‘this man was brought to us from Russia. Precisely such a case of '''vitiated judgment as I describe at length in my Treatise on Madness. Mayhap you have read it?’ — Andrew Miller, ''Ingenious Pain

to debase or morally corrupt

*1890 , Leo Tolstoy,

*:The robber does not intentionally vitiate people, but the governments, to accomplish their ends, vitiate whole generations from childhood to manhood with false religions and patriotic instruction.

(archaic) to violate, to rape

* 1965': ‘Crush the cockatrice,’ he groaned, from his death-cell. ‘I am dead in law’ – but of the girl he denied that he had ‘attempted to '''vitiate her at Nine years old’; for ‘upon the word of a dying man, both her Eyes did see, and her Hands did act in all that was done’. — John Fowles, ''The Magus

to make something ineffective, to invalidate

*{{quote-book

, author = , title = , year = 1734 , page = 78 , passage = ...all the hinges of the animal frame are subverted, every animal function is vitiated ; the carcass retains but just life enough to make it capable of suffering. }}

Verb

(es)

To morally corrupt (someone); to seduce.

* 1727 , , The History of the Devil , ch. 9:

But the Devil had met with too much Success in his first Attempts, not to go on with his general Resolution of debauching the Minds of Men, and bringing them off from God.

To debase (something); to lower the value of (something).

* 2014 March 23, , " Peter Hitchens's Blog: 23 March 2014 1:41 AM," The Mail on Sunday (UK) (retrieved 18 April 2014):

[S]aving of all kinds is pointless when interest is microscopic and state-sponsored inflation is debauching the currency.