From un- + taintable. <span class="searchmatch">untaintable</span> (comparative more <span class="searchmatch">untaintable</span>, superlative most <span class="searchmatch">untaintable</span>) Not able to be tainted, incorruptible. 1997, Mark Jenkins...
bus staring at the storm burying the highway and the sagebrush and the antelope, Mike and I were trembling from an <span class="searchmatch">untaintable</span>, undauntable expectancy....