The word "Chickasaw" has a couple of meanings, so let's break it down in a simple way for better understanding.
In more advanced contexts, you might discuss the Chickasaw Nation, which is a legally recognized government of the Chickasaw people today. You could say: - "The Chickasaw Nation has its own government and provides various services to its members."
There are no direct synonyms for "Chickasaw" since it is a specific term referring to a particular group of people and their language. However, you could refer to them as "Native Americans" in a more general context, but that would not be as specific.
There are no common idioms or phrasal verbs that include the word "Chickasaw," as it is a proper noun.
In summary, "Chickasaw" is an important term related to a specific Native American tribe and their language.