This is the 11444th most frequent French word.
replonge
"Replonge" means "plunges again" or "dives back."
The word 'replonge' here refers to the act of mentally diving back into one's memories.
Il replonge dans ses souvenirs chaque fois qu'il voit cette photo.
He plunges back into his memories every time he sees this photo.
In this sentence, 'replonge' indicates returning to or relapsing into a previous state, in this case, bad habits.
Après avoir réussi à se relever, il replonge dans ses mauvaises habitudes.
After managing to recover, he falls back into his bad habits.
Here, 'replonge' refers to the physical act of plunging or immersing an object repeatedly into a liquid.