simple past tense and past participle of taint
"The entire batch of milk was tainted when a few drops of cleaning fluid accidentally fell into it during processing."
Corrupted or filled with imperfections.
"The reputation of the once-respected firm was tainted by a series of ethical scandals that revealed deep flaws in its leadership."
The word "tainted" comes from the verb "taint," which originally meant to contaminate or corrupt something pure. The suffix "-ed" is added to indicate that this action has been completed.