Source : Webster's Revised Unabridged Dictionary (1913)

Rebel \Reb"el\, a. [F. rebelle, fr. L. rebellis. See {Rebel}, v.
   t.]
   Pertaining to rebels or rebellion; acting in revolt;
   rebellious; as, rebel troops.

         Whoso be rebel to my judgment.           --Chaucer.

         Convict by flight, and rebel to all law. --Milton.

Rebel \Reb"el\, n. [F. rebelle.]
   One who rebels.

   Syn: Revolter; insurgent.

   Usage: {Rebel}, {Insurgent}. Insurgent marks an early, and
          rebel a more advanced, stage of opposition to
          government. The former rises up against his rulers,
          the latter makes war upon them.

Rebel \Re*bel"\, v. i. [imp. & p. p. {Rebelled}; p. pr. & vb. n.
   {Rebelling}.] [F. rebeller, fr. L. rebellare to make war
   again; pref. re- again + bellare to make war, fr. bellum war.
   See {Bellicose}, and cf. {Revel} to carouse.]
   1. To renounce, and resist by force, the authority of the
      ruler or government to which one owes obedience. See
      {Rebellion}.

            The murmur and the churl's rebelling. --Chaucer.

            Ye have builded you an altar, that ye might rebel
            this day against the Lord.            --Josh. xxii.
                                                  16.

   2. To be disobedient to authority; to assume a hostile or
      insubordinate attitude; to revolt.

            Hoe could my hand rebel against my heart? How could
            you heart rebel against your reason?  --Dryden.

Source : WordNet®

Rebel
     n 1: `johnny' was applied as a nickname for Confederate soldiers
          by the Federal soldiers in the American Civil War;
          `grayback' derived from their gray Confederate uniforms
          [syn: {Reb}, {Johnny Reb}, {Johnny}, {grayback}]
     2: a person who takes part in an armed rebellion against the
        constituted authority (especially in the hope of improving
        conditions) [syn: {insurgent}, {insurrectionist}, {freedom
        fighter}]
     3: someone who exhibits great independence in thought and
        action [syn: {maverick}]
     v 1: take part in a rebellion; renounce a former allegiance [syn:
           {arise}, {rise}, {rise up}]
     2: break with established customs [syn: {renegade}]