Formal:
* Mahāshāy (महशय) - This is a common, respectful term used for men. It's similar to "Mr." in English.
* Shrimān (श्रीमान) - This is another formal term, similar to "Mr." but slightly more formal.
* Sahib (साहिब) - This term has a colonial history, but it's still used in some contexts, particularly in northern India, to address someone in a formal, respectful way.
* Ji (जी) - This is a respectful suffix added after a person's name, like "Mr. Sharma Ji". It indicates politeness and respect.
Informal:
* Bhai (भाई) - This means "brother" and can be used to address someone informally, like "bro" in English.
* Yaar (यार) - This means "friend" and can be used to address someone casually.
* Sahab (साहब) - This is a more informal version of "Sahib" and can be used to address someone casually, particularly in the north.
Other considerations:
* Age and social status: It's important to consider the age and social status of the person being addressed.
* Region: Different regions in India have different dialects and levels of formality.
* Relationship: The relationship between the speaker and the listener is also important. A more casual term would be appropriate between friends, while a more formal term would be appropriate when addressing a superior.
It's always best to err on the side of formality and use a respectful term, especially if you are unsure of the appropriate word.