The word radioactivating essentially means to make something radioactive or to increase its level of radioactivity. Therefore, some of the antonyms for this term could include decontaminating, purifying, cleaning, detoxifying, and sterilizing. These are all processes that remove radioactive substances or decrease their level of activity in a given material or environment. Other antonyms could be preventative measures such as shielding, blocking, or isolating, which protect against radiation exposure altogether. With the growing concern and awareness around the harmful effects of radiation, it is important to focus on finding effective antonyms to radioactivating processes to protect ourselves, our environment, and other living creatures from its negative impacts.