Possibly from French or Middle French rouiller (“to rust, make muddy”), from Old French rouil (“mud, rust”), from Vulgar Latin *robicula, from Latin robigo (“rust, blight”)
roil (third-person singular simple present roils, present participle roiling, simple past and past participle roiled)
- To render turbid by stirring up the dregs or sediment of
- To annoy; to make someone angry.
- (intransitive) To bubble, seethe.
- (obsolete, intransitive) To wander; to roam.
- (obsolete, Britain, dialectal, intransitive) To romp.