The word “deleterious” is an adjective that describes something that has a harmful, damaging, or detrimental effect on something else, often used in the context of health, well-being, or the overall quality of something. For example, if a substance or action is said to have deleterious effects on one’s health, it means that it is causing harm or negative consequences to their health. In general, “deleterious” is used to convey the idea that something is harmful or injurious in some way.