Vitiate (verb)

To impair or spoil the quality or efficiency of; to weaken or corrupt the moral character of.

Origin:

Late latin vitiare, from latin vitium.

Examples:

1. The air pollution had vitiated the purity of the mountain stream.
2. The lawyer argued that the defendant"s confession had been vitiated by the police"s use of torture.
3. The judge ruled that the evidence was inadmissible because it had been vitiated by the prosecution's failure to follow proper procedures.
4. The new regulations are intended to vitiate the incentives for companies to pollute the environment.
5. The scandal had vitiated the public's trust in the government.