Pyrogenous is a technical term that is used to refer to substances that are capable of causing fever. Some synonyms for this term include febrifugal, febrifacient, pyretic, and feverish. Febrifugal and febrifacient are terms that are often used in reference to medications that are used to reduce fever. Pyretic is a more general term that is used to describe anything that is capable of eliciting fever. Feverish, on the other hand, is an adjective that is used to describe someone who is experiencing a fever or who has fever-like symptoms. Overall, these synonyms are useful for describing anything related to fever, including medications, symptoms, and other factors that might contribute to fever.