The word "taintest" means to slightly contaminate or spoil something. Some synonyms for this word include infect, corrupt, pollute, tarnish, defile, poison, adulterate, or mar. These words suggest the idea of some impure or harmful substance being introduced to something otherwise pure or pristine. For example, you might say that a small amount of dirt taints an otherwise clean surface, or that a lie taints an otherwise trustworthy person. It's important to note that some of these synonyms imply a more severe or intentional contamination than others, depending on the context they're used in.