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

• twonk
• twopence
• twopenny
• twopenny-halfpenny
• twoscore
• twosome
• Twyla Tharp
• TX
• Tyan Shan
• Tyche
• Tycho Brahe
• tycoon
• tying
• tying up
• tyiyn
• tyke
• Tylenchidae
• Tylenchus
• Tylenchus tritici
• Tylenol
• Tyler
• tympan
• tympani
• tympanic
• tympanic bone