être vert de jalousie

to be extremely jealous

This expression means to be consumed by jealousy, very similar to the English "green with envy."

Quand elle a vu la nouvelle voiture de son voisin, elle était verte de jalousie.

When she saw her neighbour's new car, she was green with envy.

The link between green and negative emotions traces back to ancient Greek medicine, where anger and jealousy were thought to cause an overproduction of bile, giving the skin a greenish tint. In French, 'vert de colère' (green with anger) came first, and 'vert de jalousie' followed. Shakespeare made the same connection in English with the 'green-eyed monster' in Othello.