1. Characterized by effort to the point of exhaustion; especially physical effort
   "a gruelling campaign"
   - arduous, backbreaking, grueling [US], hard, heavy, laborious, operose, punishing, toilsome

See also: effortful

• propertyless
• prophase
• prophecy
• prophesier
• prophesy
• prophet
• prophetess
• prophetic
• prophetical
• prophetically
• Prophets
• prophylactic
• prophylactic device
• prophylaxis
• prophyll
• propinquity
• propionaldehyde
• propionic acid
• propitiate
• propitiation
• propitiative
• propitiator
• propitiatory
• propitious
• propitiously