Where does “enrouiller” come from?

enrouiller (French) comes from French rouille, from Old French reoïlle, from Vulgar Latin robicla, from Latin robicula, from Latin rōbīgō, from Latin rōbus, from Proto-Italic rouβos, from Proto-Indo-European h₁rewdʰ- — red.

enrouiller (French): to rust, rust up

Definitions

to rust, rust up

Ancestry of “enrouiller”, step by step

Step	Language	Word	Meaning
1	French	rouille	rust; rouille
2	Old French	reoïlle	—
3	Vulgar Latin	robicla	—
4	Latin	robicula	—
5	Latin	rōbīgō	rust
6	Latin	rōbus	red
7	Proto-Italic	rouβos	—
8	Proto-Indo-European	h₁rewdʰ-	red

Every word from Proto-Indo-European h₁rewdʰ- →Every word from Proto-Italic rouβos →Every word from Latin rōbus →