Contaminative refers to something that causes contamination or pollution. Its antonyms, therefore, are words that mean the opposite - something that purifies or cleanses. One antonym is 'purifying', which implies removing impurities and pollutants to make something clean and fresh. Other antonyms include 'sterilizing', 'disinfecting,' and 'sanitizing.' These words are often associated with processes used to clean and purify spaces, surfaces or objects. Some more common antonyms for contaminative include 'clean,' 'pure,' 'fresh,' and 'healthy.' These opposites can be useful when describing the state of things like water, air, or food, and the acts necessary to restore purity.