Strenuous
Else clues• Against difficulties
• Against the odds
• Arduous
• Difficult
• Direction for Sisyphus
• Grueling
• Kind of ascent
• Laborious
• Like a tough battle
• Like an arduous battle
• Like difficult struggles
• Like Jack and Jill's path
• Like some battles
• Toward the mountain's peak
• Toward the summit
• Type of battle
• The upward slope of a hill