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

• saddle horn
• saddle horse
• saddle of lamb
• saddle oxford
• saddle oyster
• saddle point
• saddle roof
• saddle seat
• saddle shoe
• saddle soap
• saddle stitch
• saddle-shaped
• saddle-sore
• saddleback
• saddleback roof
• saddlebag
• saddlebill
• saddlebow
• saddlecloth
• excitement
• exciter
• exciting
• excitingly
• exclaim
• exclaiming