This is the 508th most frequent Hungarian word.
fehér
"Fehér" means "white" in English.
Here, 'fehérek' is the plural form of the adjective 'white', agreeing in number with the plural noun 'falai' (walls).
A szoba falai fehérek voltak.
The walls of the room were white.
The word 'fehér' modifies the noun 'ingem' (my shirt), specifying its color as white.
A fehér ingem már nem fér rám.
My white shirt no longer fits me.
'Fehér' is used here to attribute the color white to 'hó' (snow), stating a general characteristic.