Formal:
* 爸爸 (bàba) - This is the most common and general term for "father". It is appropriate in most situations.
Informal:
* 爸爸 (bàba) - Can also be used informally, especially with younger children.
* 爹 (diē) - This is a more informal term for "father", often used by children or in a more intimate setting.
* 老爸 (lǎobà) - This literally means "old father" and is a more affectionate and informal term.
Other options:
* 父亲 (fùqīn) - This is a more formal term for "father" and is often used in written or official contexts.
* 老爹 (lǎodiē) - This is a more informal and affectionate term, similar to "old man" or "dad".
Choosing the right term:
The best way to choose the right term is to consider the context and your relationship with the person you are speaking to. If you are speaking to a child or in a casual setting, "爸爸 (bàba)" or "老爸 (lǎobà)" are good choices. If you are speaking in a formal setting or to someone you don't know well, "爸爸 (bàba)" or "父亲 (fùqīn)" are more appropriate.