v.
 (flogs, flogging, flogged)
    - beat with a whip or stick as a punishment.
 - informal work at or promote repetitively or at excessive length.
 - Brit. informal sell or offer for sale.
 - Brit. informal make one's way with strenuous effort.
 
 
  Phrase
  
    
      - flog a dead horse
 Brit. waste energy on a lost cause or unalterable situation. 
    
   
  Derivative
  
  Etymology
  C17 (orig. sl.): perh. imitative, or from L. flagellare ‘to whip’.