The Collaborative International Dictionary of English v.0.48:

Rascal \Ras"cal\, a.
   Of or pertaining to the common herd or common people; low;
   mean; base. "The rascal many." --Spencer. "The rascal
   people." --Shak.
   [1913 Webster]

         While she called me rascal fiddler.      --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rascal \Ras"cal\ (r[a^]s"kal), n. [OE. rascaille rabble,
   probably from an OF. racaille, F. racaille the rabble,
   rubbish, probably akin to F. racler to scrape, (assumed) LL.
   rasiculare, rasicare, fr. L. radere, rasum. See Rase, v.]
   [1913 Webster]
   1. One of the rabble; a low, common sort of person or
      creature; collectively, the rabble; the common herd; also,
      a lean, ill-conditioned beast, esp. a deer. [Obs.]
      [1913 Webster]

            He smote of the people seventy men, and fifty
            thousand of the rascal.               --Wyclif (1
                                                  Kings [1
                                                  Samuel] vi.
                                                  19).
      [1913 Webster]

            Poor men alone? No, no; the noblest deer hath them
            [horns] as huge as the rascal.        --Shak.
      [1913 Webster]

   2. A mean, trickish fellow; a base, dishonest person; a
      rogue; a scoundrel; a trickster.
      [1913 Webster]

            For I have sense to serve my turn in store,
            And he's a rascal who pretends to more. --Dryden.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rascal
    n 1: a deceitful and unreliable scoundrel [syn: rogue,
         knave, rascal, rapscallion, scalawag, scallywag,
         varlet]
    2: one who is playfully mischievous [syn: imp, scamp,
       monkey, rascal, rapscallion, scalawag, scallywag]

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "rascal":
   bad boy, bastard, blackguard, blighter, booger, bounder, buffoon,
   bugger, cad, cutup, dastard, devil, elf, enfant terrible, funmaker,
   good-for-nothing, heel, hood, hoodlum, hooligan, imp, joker,
   jokester, knave, little devil, little monkey, little rascal,
   lowlife, minx, mischief, mischief-maker, miscreant, pixie,
   practical joker, prankster, precious rascal, puck, rapscallion,
   rogue, rotter, rowdy, ruffian, scalawag, scamp, scapegrace,
   scoundrel, shyster, sneak, spalpeen, villain, wag, wastrel,
   wretch



The Devil's Dictionary (1881-1906):

RASCAL, n.  A fool considered under another aspect.