This is the 165th most frequent Czech word.
nejvyšší
"Nejvyšší" means "the highest" or "supreme" in English.
Here, 'nejvyšší' is used as a superlative adjective describing the quality of the mountain as the highest in relation to others.
Nejvyšší hora České republiky je Sněžka.
The highest mountain in the Czech Republic is Sněžka.
In this instance, 'nejvyšší' is also a superlative adjective, indicating that this building ranks within the group of tallest buildings.
Tato stavba patří mezi nejvyšší v celé Evropě.
This building is among the tallest in all of Europe.
Here, 'nejvyšší' is used metaphorically as a superlative to describe the level of efficiency of the solution being sought.