This is the 12285th most frequent French word.
éclairée
"Éclairée" means "enlightened" or "illuminated."
Here, 'éclairée' is the past participle of 'éclairer' used as an adjective to describe the room's lighting conditions.
La salle était bien éclairée.
The room was well-lit.
In this sentence, 'éclairée' is used metaphorically to describe someone's high level of understanding or wisdom regarding a topic.
Elle est une personne très éclairée sur le sujet.
She is a very enlightened person on the subject.
Here, 'éclairée' again functions as the past participle of 'éclairer' describing the act of lighting provided by streetlights.