n.
 a mischievous or impudent person, especially a child. 
▸a dishonest or untrustworthy man.
 
  Derivative
  
    - rascality n. 
(pl. rascalities)
.  - rascally adj.
 
   
  Etymology
  ME (in the senses ‘a mob’ and ‘member of the rabble’): from OFr. rascaille ‘rabble’, of uncertain origin.