arduous /ärˈdū-əs/

1. Steep, difficult to climb
2. Difficult to accomplish
3. Laborious

• paddle-staff
• paddle-staffs
• paddle steamer
• paddle steamers
• paddle wheel
• paddle wheels
• paddle-wood
• paddle-woods
• paddling
• paddlings
• paddock
• paddocks
• paddock-stool
• paddock-stools
• paddy
• Paddy
• paddy-bird
• paddy-birds
• paddy field
• paddy fields
• Paddyism
• paddymelon
• paddymelons
• Paddys
• Paddy's lantern