Formal:
* Adéu: This is the most formal way to say goodbye. It's similar to "farewell" in English.
* Fins aviat: This means "see you soon" and is a more polite way to say goodbye than simply "adéu."
* Fins demà: This means "see you tomorrow" and is appropriate if you'll be seeing the person again the next day.
Informal:
* Adeu: This is a more casual way to say goodbye, similar to "goodbye" in English.
* Fins a la vista: This means "see you later" and is a common way to say goodbye to friends.
* Fins al proper: This means "until next time" and is appropriate for a more casual farewell.
* Ciao: This is a borrowed word from Italian that is also common in Catalan.
Other options:
* Bon dia: This means "good day" and can be used as a way to say goodbye in the morning.
* Bona tarda: This means "good afternoon" and can be used as a way to say goodbye in the afternoon.
* Bona nit: This means "good night" and can be used as a way to say goodbye in the evening.
The best way to choose the appropriate goodbye is to consider the context and your relationship with the person you're saying goodbye to.