The Collaborative International Dictionary of English v.0.48:

Dispel \Dis*pel"\, v. t. [imp. & p. p. Dispelled; p. pr. & vb.
   n. Dispelling.] [L. dispellere; dis- + pellere to push,
   drive. See Pulse a beating.]
   To drive away by scattering, or so to cause to vanish; to
   clear away; to banish; to dissipate; as, to dispel a cloud,
   vapors, cares, doubts, illusions.
   [1913 Webster]

         [Satan] gently raised
         their fainting courage, and dispelled their fears.
                                                  --Milton.
   [1913 Webster]

         I saw myself the lambent easy light
         Gild the brown horror, and dispel the night. --Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dispel
    v 1: force to go away; used both with concrete and metaphoric
         meanings; "Drive away potential burglars"; "drive away bad
         thoughts"; "dispel doubts"; "The supermarket had to turn
         back many disappointed customers" [syn: chase away,
         drive out, turn back, drive away, dispel, drive
         off, run off]
    2: to cause to separate and go in different directions; "She
       waved her hand and scattered the crowds" [syn: disperse,
       dissipate, dispel, break up, scatter]

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "dispel":
   attenuate, be consumed, be gone, blow off, break up, cast forth,
   cast off, cease, cease to be, cease to exist, clear away, crumble,
   dematerialize, depart, die, die away, die out, dilute, disappear,
   disband, disintegrate, dismiss, disperse, dissipate, dissolve,
   diverge, do a fade-out, do away with, drive away, dwindle, eject,
   eliminate, erode, evanesce, evaporate, exit, expel, exterminate,
   fade, fade away, fade out, flee, fling off, fly, get rid of, go,
   go away, go separate ways, hide, leave no trace, leave the scene,
   liquidate, melt, melt away, oust, part, part company, pass,
   pass away, pass out, perish, purge, retire from sight, scatter,
   separate, shake off, shoo, sink, sink away, split up,
   suffer an eclipse, thin, thin out, throw away, throw off,
   unimportant, vanish, vanish from sight, volatilize, waste,
   waste away, wear away