Formal:
* Mitra: This is a more formal and polite way to say "friend."
* Saathi: This word means "companion" and is also often used in a formal setting.
* Hamsafar: This literally means "traveler together" and implies a close companion on a journey.
Informal:
* Yaar: This is a very common and friendly way to say "friend."
* Bhai/Behen: This means "brother" or "sister" and is used to refer to a very close friend.
* Dostana: This word emphasizes the friendship itself.
Other:
* Snehita: This is a more poetic and literary word for "friend."
* Bandhu: This means "brother" or "kinsman" and can be used to refer to a very close friend.
The best word to use will depend on the specific situation and the relationship you have with the person you are referring to.