Inquinate, meaning to pollute or contaminate, can be replaced with various synonyms depending on the context it is used in. One such synonym is contaminate, which usually suggests the presence of harmful materials. Taint can also be used to describe a contaminant that impairs or reduces the quality of something. Another synonym that can be used is defile, which highlights the idea of desecrating something pure or sacred. Other synonyms for inquinate include pollute, corrupt, infect, and poison. These words all describe the negative impact of a substance or action on the environment, a system, or an individual.