Immission refers to the introduction or release of a substance or energy into the environment. There are several synonyms for this word, including emission, discharge, effluent, pollution, and contamination. Emission refers to the release of gases, liquids, or particles into the air, while discharge refers to the release of substances into water bodies. Effluent refers to any liquid waste product that is released into the environment, while pollution refers to the introduction of any substance that causes harm to the environment or living beings. Contamination refers to the presence of harmful or unwanted substances in a given environment. All of these terms help to describe the negative impacts that can result from the immission of substances or energy into the environment.