This is the 4394th most frequent French word.
grise
Gray (feminine).
Here, 'grise' is used as an adjective to describe the color of the car (feminine singular), agreeing with 'voiture', which is feminine.
La voiture est grise.
The car is gray.
In this case, 'grise' is figuratively used as an adjective describing a mood, imbuing it with a sense of dullness or melancholy.
Elle a une humeur grise aujourd'hui.
She is in a gloomy mood today.
'grisé' is applied here as part of the adjectival form to describe the paper, slightly modified to express a grayish quality.