Roil \Roil\, v. t. [imp. & p. p. Roiled; p. pr. & vb. n. Roiling.]

[Cf. OE. roilen to wander; possibly fr. OF. roeler to roll, equiv. to F. rouler. See Roll, v., and cf. Rile.]

1. To render turbid by stirring up the dregs or sediment of; as, to roil wine, cider, etc., in casks or bottles; to roil a spring.

2. To disturb, as the temper; to ruffle the temper of; to rouse the passion of resentment in; to perplex.

That his friends should believe it, was what roiled him [Judge Jeffreys] exceedingly. --R. North.

Note: Provincial in England and colloquial in the United States. A commoner, but less approved, form is rile.

Source: Webster's Revised Unabridged Dictionary (1913)