This is the 333rd most frequent Icelandic word.
uppi
"Uppi" means "up," "above," or "upstairs" in English.
Here, 'uppi' refers to being situated at a higher location, specifically on the mountain.
Við fórum uppi á fjall.
We went up the mountain.
In this context, 'uppi' denotes being at an upper level, in this case, upstairs in a building.
Ljósin voru ennþá kveikt uppi.
The lights were still on upstairs.
Here, 'uppi' is used metaphorically to mean 'openly' and 'in plain sight' rather than being physically above.