Kinin is a term used to describe a type of peptide molecule that is involved in various physiological processes such as inflammation and vascular permeability. However, there are a few synonyms that can be used to describe kinins, such as bradykinin and kallidin. These two terms are closely related to kinins and are often used interchangeably to describe the same type of peptide molecule. Another synonym for kinin is "vasodilator peptide," which refers to its ability to cause the dilation of blood vessels. Overall, while kinin is the most common term used to describe this peptide molecule, there are several synonyms that can be used depending on the context.