The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\, a.
   Of or pertaining to a rabble; like, or suited to, a rabble;
   disorderly; vulgar. [R.] --Dryden.
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The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\, v. t. [imp. & p. p. Rabbled (r[a^]b"b'ld);
   p. pr. & vb. n. Rabbling (r[a^]b"bl[i^]ng).]
   1. To insult, or assault, by a mob; to mob; as, to rabble a
      curate. --Macaulay.
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            The bishops' carriages were stopped and the prelates
            themselves rabbled on their way to the house. --J.
                                                  R. Green.
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   2. To utter glibly and incoherently; to mouth without
      intelligence. [Obs. or Scot.] --Foxe.
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   3. To rumple; to crumple. [Scot.]
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The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\ (r[a^]b"b'l), n. [Etymol. uncertain.] (Iron
   Manuf.)
   An iron bar, with the end bent, used in stirring or skimming
   molten iron in the process of puddling.
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The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\, v. t.
   To stir or skim with a rabble, as molten iron.
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The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\, v. i. [Akin to D. rabbelen, Prov. G. rabbeln,
   to prattle, to chatter: cf. L. rabula a brawling advocate, a
   pettifogger, fr. rabere to rave. Cf. Rage.]
   To speak in a confused manner. [Prov. Eng. & Scot.]
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The Collaborative International Dictionary of English v.0.48:

Rabble \Rab"ble\, n. [Probably named from the noise made by it
   (see Rabble, v. i.) cf. D. rapalje rabble, OF. & Prov. F.
   rapaille.]
   1. A tumultuous crowd of vulgar, noisy people; a mob; a
      confused, disorderly throng.
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            I saw, I say, come out of London, even unto the
            presence of the prince, a great rabble of mean and
            light persons.                        --Ascham.
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            Jupiter, Mercury, Bacchus, Venus, Mars, and the
            whole rabble of licentious deities.   --Bp.
                                                  Warburton.
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   2. A confused, incoherent discourse; a medley of voices; a
      chatter.
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   The rabble, the lowest class of people, without reference
      to an assembly; the dregs of the people. "The rabble call
      him `lord.'" --Shak.
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WordNet (r) 3.0 (2006):

rabble
    n 1: a disorderly crowd of people [syn: mob, rabble, rout]
    2: disparaging terms for the common people [syn: rabble,
       riffraff, ragtag, ragtag and bobtail]

The Devil's Dictionary (1881-1906):

RABBLE, n.  In a republic, those who exercise a supreme authority
tempered by fraudulent elections.  The rabble is like the sacred
Simurgh, of Arabian fable -- omnipotent on condition that it do
nothing.  (The word is Aristocratese, and has no exact equivalent in
our tongue, but means, as nearly as may be, "soaring swine.")