This is the 9752nd most frequent French word.
envahissent
"Envahissent" means "they invade" or "they overwhelm."
In this sentence, 'envahissent' refers to the unwelcome and spreading presence of weeds in the garden.
Les mauvaises herbes envahissent notre jardin chaque été.
The weeds invade our garden every summer.
Here, 'envahissent' symbolizes the pervasive and intrusive nature of negative thoughts occupying one's mind.
Les pensées sombres envahissent son esprit quand elle est seule.
Dark thoughts invade her mind when she is alone.
In this context, 'envahissent' describes the overwhelming influx of tourists to the beaches, giving a sense of crowding.