The word "animal" is often used to refer to any living sentient being that is not a human being. However, there are many different types of animals out there, each with their own unique features and characteristics. Some common synonyms for the word "animal" include "creature," "beast," "critter," "living being," and "brute." There are also more specific synonyms, such as "mammal," "reptile," "bird," "fish," and "insect." Each of these synonyms helps to further differentiate between different types of animals and can be useful in providing more context to a conversation about the animal kingdom.