The Collaborative International Dictionary of English v.0.48:

Roil \Roil\, v. i.
   1. To wander; to roam. [Obs.]
      [1913 Webster]

   2. To romp. [Prov. Eng.] --Halliwell.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. To disturb, as the temper; to ruffle the temper of; to
      rouse the passion of resentment in; to perplex.
      [1913 Webster]

            That his friends should believe it, was what roiled
            him [Judge Jeffreys] exceedingly.     --R. North.
      [1913 Webster]

   Note: Provincial in England and colloquial in the United
         States. A commoner, but less approved, form is rile.
         [1913 Webster]

WordNet (r) 3.0 (2006):

roil
    v 1: be agitated; "the sea was churning in the storm" [syn:
         churn, boil, moil, roil]
    2: make turbid by stirring up the sediments of [syn: roil,
       rile]

Moby Thesaurus II by Grady Ward, 1.0:

178 Moby Thesaurus words for "roil":
   adiaphanousness, aggravate, agitate, agitation, annoy, arouse,
   badger, bait, be at, be turbulent, beat, beat up, bedevil, beset,
   bluster, bobbery, boil, boiling, bother, bristle, brouhaha,
   brown off, bug, bullyrag, burn up, bustle, carouse, chafe, chivy,
   churn, churn up, cloudiness, commotion, conturbation, convulse,
   create a disturbance, create a riot, cut loose, darkness, devil,
   dimness, disarrange, discompose, discomposure, disorder, disquiet,
   disquietude, distemper, disturb, disturbance, dog, ebullition,
   embitter, embroilment, exasperate, excite, excitement, exercise,
   fash, ferment, fermentation, fever, feverishness, fidgets, flap,
   flurry, fluster, flutteration, foment, fret, fume, fuss, get,
   go berserk, gripe, harass, harry, heckle, hector, hound, hubbub,
   huff, hurly-burly, imperviousness to light, incense, inflame,
   inquietude, intransparency, irk, irritate, jitters, jumpiness,
   maelstrom, make a commotion, make an ado, make trouble, malaise,
   miff, mill, mill around, moil, molest, nag, needle, nerviness,
   nervosity, nervousness, nettle, nudzh, obscurity, opacity, opaque,
   opaqueness, paddle, peeve, persecute, perturb, perturbate,
   perturbation, pester, pick on, pique, plague, pluck the beard,
   pother, provoke, raise a ruckus, raise a rumpus, raise a storm,
   rankle, restlessness, ride, rile, riot, ripple, roiledness,
   roister, roughen, rout, row, ruffle, rumple, run amok, run riot,
   run wild, seethe, seething, set up, shake, shake up, stir,
   stir the blood, stir up, swirl, tease, to-do, torment, trepidation,
   trepidity, trouble, try the patience, tumult, tumultuation,
   turbidity, turbidness, turbulence, turmoil, tweak the nose,
   twitter, unease, unrest, upset, vex, whip, whip up, whisk, work up,
   worry