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

See also: effortful, operoseness

• aromatic
• aromatic aster
• aromatic compound
• aromatic hydrocarbon
• aromatise
• aromatize
• Arouet
• around
• around the bend
• around-the-clock
• arousal
• arouse
• aroused
• arouser
• Arp
• arpeggio
• arpent
• arquebus
• arrack
• arraign
• arraignment
• arrange
• arranged
• arrangement
• arranger