punishing

Adjective

• characterized by effort to the point of exhaustion; especially physical effort
  • worked their arduous way up the mining valley
    
  • a grueling campaign
    
  • hard labor
    
  • heavy work
    
  • heavy going
    
  • spent many laborious hours on the project
    
  • set a punishing pace
    

• resulting in punishment
  • the king imposed a punishing tax