arduous
AR-joo-usadjMeaning needing great effort; hard and tiring
Memory hook HARD-uous: a steep, HARD climb. The trail rises like a wall, and Tia and Marcus puff up it one step at a time: the climb is arduous.
The arduous climb took six hours, almost all of it uphill.
In context Restoring the old ship was arduous: volunteers spent four winters scraping, sanding and replacing every rotten plank by hand.
Similar strenuous, demanding, grueling, laborious
Opposite easy, effortless, light
From Latin arduus, “steep, high, difficult.”