There are various synonyms for the term "toxic substance". Some common synonyms include poisonous substance, harmful chemical, dangerous agent, noxious material, and hazardous waste. These synonyms are used to describe substances that can cause harm or death to humans, animals, or the environment if they are improperly handled or disposed of. Toxic substances come in various forms such as solid, liquid, or gaseous state. They can also be natural or man-made. It is important to understand the potential dangers that toxic substances can pose and take the necessary precautions to protect ourselves and the environment from their harmful effects.