It's both formal and informal. It depends on how you say it. If you say "Adiós, señora." it's formal. If you say "Adiós, amigo." it's informal.
Formal
"Hasta luego" is neither formal nor informal, it straddles the middle between them and can be used in most situations. If you want a truly formal way of saying goodbye, "Adios" is probably the most formal. "Chao" correspondingly, should only be used between close friends or family members who are your age or younger.
formal
Formal
Usted is the formal way of saying 'you'.
Formal
"Adiós, señor" is a formal expression. The use of "señor" indicates respect and politeness, making it suitable for addressing someone in a formal context. It is appropriate in situations such as parting from someone you don't know well or in professional settings. In contrast, a more informal farewell would omit "señor" or use a more casual greeting.
it is an informal group
"Adios" is a Spanish term used to say goodbye or farewell. It is a formal and respectful way to part ways with someone.
"Hasta luego" is neither formal nor informal, it straddles the middle between them and can be used in most situations. If you want a truly formal way of saying goodbye, "Adios" is probably the most formal. "Chao" correspondingly, should only be used between close friends or family members who are your age or younger.
formal is the cinema and informal is a gay man
informal
formal and informal rhythm
what is formal and informal communication
formal
adios hasta luego (more informal, short-term)
There is no formal slang. Slang is informal language.