Ultrapure is a term that describes something that is extremely pure, with little to no impurities present. However, as with many words in the English language, there are also antonyms for ultrapure. These include impure, contaminated, tainted, polluted, and adulterated. In many contexts, these words are used to describe substances that are far from pure, and often carry negative connotations. For example, polluted water or adulterated food are things that we want to avoid at all costs, as they can be harmful to our health. In contrast, ultrapure substances are highly sought after in many industries, particularly those that require strict quality control and adherence to standards.