労力
ろうりょく · rouryoku · JLPT N1 · noun
effort
💪 労力 = 労 (toil, labor) + 力 (strength, power): the strength you spend when you toil
労 means toil or hard work, and 力 means power or strength. Together they name the effort and labor you put into a task, including the trouble it causes.
力 — pictograph of a plow or arm muscle
力 originated as a pictograph of an ancient plow, the main tool requiring physical exertion in early agriculture. Some scholars also see it as a flexed arm showing muscle. From this concrete image it broadened to mean 'strength, power, force, effort'.