Informal:
* Copain: This is the French word for "friend," and it's commonly used in Cajun culture.
* Mon ami: This is another French phrase, meaning "my friend." It can be used for close friends.
* Mon cher: This means "my dear" and is often used affectionately, similar to "buddy."
* Partenaire: This is a more formal term for "partner" but can be used in a friendly way, especially among men.
* Cher: This is a simple and common term of endearment, similar to "dear" or "honey."
* Mon ami, mon ami: This is a playful and affectionate way to say "my friend."
More formal:
* Ami: This is the simple French word for "friend," but it can be used more formally than "copain."
* Compagnon: This means "companion" and can be used in a formal setting.
The best way to choose the right word is to consider the relationship between the speakers and the tone of the conversation.