roil means to render turbid by stirring up the dregs or sediment of.
roil is pronounced /ˈɹɔɪl/.
Why “roil” is a great word
To stir up sediment in a liquid, making it turbid, or to deeply agitate or irritate someone. Its origin is uncertain, possibly from Old French *roil* (“mud, rust”) or *rouiller* (“to rust, make muddy”), from Vulgar Latin *robicula*, from Latin *robigo* (“rust”); first recorded in English between 1580 and 1590. Unlike “rile,” which is solely about provoking a person, or “agitate,” which broadly describes disturbance, to “roil” carries the primal, particulate sense of churning a settled medium into opacity. It is the oar disturbing the pond’s floor so that light vanishes into brown swirl, the gossip that clouds a tranquil reputation, and the unresolved grievance left to swirl in the dark of the mind—a reminder that clarity is fragile, and the past is never fully settled silt.
Etymology
Origin uncertain. 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”)
verb
- To render turbid by stirring up the dregs or sediment of.e.g.“to roil wine, cider, etc, in casks or bottles”
- To annoy; to make angry; to throw into discord.e.g.“That his friends should believe it, was what roiled him exceedingly.”
- To bubble, seethe.
- To romp or tumble.e.g.“The finale was a romp in which the entire troupe burst out of the bouldering cave and roiled along the walls.”