Merriam-Webster's Collegiate® Dictionary, 11th Edition
TAINT
I. verb see: tinge
Date: 1573
transitive verb to contaminate morally ; corrupt , to affect with putrefaction ; spoil , to touch or affect slightly with something bad , intransitive verb to become weak, to become affected with putrefaction ; spoil , see: contaminate
II. noun
Date: 1601
a contaminating mark or influence , taintless adjective