taint

contaminate, taint, pollute, defile mean to make impure or unclean. contaminate implies intrusion of or contact with dirt or foulness from an outside source.

• • water contaminated by industrial wastes

taint stresses the loss of purity or cleanliness that follows contamination.

• • tainted meat
• • a politician's tainted reputation

pollute, sometimes interchangeable with contaminate, distinctively may imply that the process which begins with contamination is complete and that what was pure or clean has been made foul, poisoned, or filthy.

• • the polluted waters of the river

defile implies befouling of what could or should have been kept clean and pure or held sacred and commonly suggests violation or desecration.

• • defile a hero's memory with slanderous innuendo