To "counteract" means to act against something in order to reduce its effect or neutralize it. For example, if a person takes a medication to counteract the side effects of another drug, they are trying to lessen the negative impact of that drug on their body. This term is often used in various fields, including medicine, chemistry, and environmental science. In everyday life, people might counteract stress by practicing relaxation techniques such as yoga or meditation. Similarly, governments may implement policies to counteract the effects of climate change, aiming to reduce pollution and promote sustainability.