This is the 7167th most frequent Swedish word.
rust
"Rust" in Swedish means "armor" or "equipment."
The word 'rost' refers to the physical rust that forms on metals.
Järnstaketet var täckt av rödbrun rost.
The iron fence was covered in reddish-brown rust.
Here, 'rost' is used metaphorically to describe something becoming stagnant or outdated.
Projektet började samla rost efter flera månaders inaktivitet.
The project started to gather rust after several months of inactivity.
In this sentence, 'rost' is figuratively used to describe skill deterioration.