¡Arriba!

[Tyrn]

Hi,

This looks and sounds very much like stand up! or get up! Even on your feet! It's just that the verb arribar does not carry any such meaning. Or I failed to find the right entry in the dictionary.

:thinking:

[Rusty]

The right entry in the dictionary would be the interjection.

This interjection is used to lift someone's mood or spirit or give encouragement, like saying, "Come on!" or "Cheer up!"
"Chin up!" or "Get up! (on your feet!)" are other meanings. This is a synonym of «¡Ánimo!».

It can also be used as a cheer, to cheer somebody on.

[Tyrn]

Thanks!

[AngelicaDeAlquezar]

I agree with Rusty.
This is the usage of the adverb "arriba" (https://dle.rae.es/arriba), as an interjection. :)