Source : Webster's Revised Unabridged Dictionary (1913)

Rapscallion \Rap*scal"lion\, n. [See {Rascallion}.]
   A rascal; a good-for-nothing fellow. [Colloq.] --Howitt.

Source : WordNet®

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