This is the 3133rd most frequent Dutch word.
duurste
Most expensive.
In this sentence, 'duurste' again serves as the superlative of 'duur', applied to the noun 'vakantie' describing it as the most expensive among a group of vacations.
Van alle vakanties die ik heb gedaan, was deze de duurste.
Of all the vacations I have taken, this one was the most expensive.
Here, 'duurste' describes the noun 'product', indicating the speaker is referring to the most expensive among various options.
Waarom kies je altijd het duurste product?
Why do you always choose the most expensive product?
Here, 'duurste' is the superlative form of 'duur' (expensive), describing the noun 'auto' as the most expensive compared to others.