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

• distichous
• distil
• distill
• distillate
• distillation
• distilled water
• distiller
• distillery
• distillment
• distinct
• distinction
• distinctive
• distinctive feature
• distinctively
• distinctiveness
• distinctly
• distinctness
• distinguish
• distinguishable
• distinguished
• Distinguished Conduct Medal
• Distinguished Flying Cross
• Distinguished Service Cross
• Distinguished Service Medal
• Distinguished Service Order