The act of rubbing one's taint on any given object. Usually done out of spite or anger.

A person who has dated,married,or had sex with someone you know is considered "tainted".

Their level of "taintedness" makes it questionable as to whether or not you should be involving yourself with that person,usually, and especially in an intimate manner.
There are several factors involved with determining the degree of a person's "taintedness", such as;

-How well one knows the person or people, that the tainted individual was with (and if you know and don't like that person, then the "taint factor" is waived and becomes more of a "Yeah, I banged that asshole's ex!)
-How long ago that relationship or encounter took place,
if that person had been with the "tainter" last night, their "taintedness" would be just about radioactive...
on the other end, there is a standard five year statute of limitations and the taint in most cases has worn off.
-Some degrees of "taint" are infinate, such as Brother's ex-wife, ex's of parents etc.
-The combinations of situations and connections are so numerous that there is no exact science for taint determination and each case must be evaluated on it's own.
In most cases there should be an individual who has the experience and knowledge to act as "Judge of the Taint" to rule on tainted individuals for you or your social circle,and that person's judgement should be taken into consideration before going ahead and doing whatever you were going to do in the first place.

to have your clean bed sheets defiled by male genitalia; especially by the grundle or taint region.

The act of, or process of claiming ownership of a seat, chair or position on a couch with your taint area, so that no one else can steal your seat.

Being taint. Having been changed by something else. Jerry was tainted by troy

A black person or a person of any race that has had sex with a black person.

a bitch who slept with more than five dudes