KanjiJLPT N3
Toil

toil, diligent, as much as possible

Mnemonic

A guy channels every last drop of power in his body to toil through crushing labor—hauling boulders uphill under a scorching sun. Sweat pours off the guy as he refuses to stop. His power isn't talent; it's raw, stubborn persistence that keeps him grinding forward.
Additional thoughts
Picture a muscular, exhausted guy straining every fiber of his being. Power here isn't magical—it's pure grit. The combination of a determined guy plus relentless power equals toil.
Quick recall
A guy pours all his power into relentless toil, refusing to quit.

Details

The keyword for 努 is toil. This kanji conveys the idea of exerting great effort, straining oneself, or working hard toward a goal. It emphasizes the strenuous, sustained nature of labor—not merely working, but pushing oneself with determination and perseverance. Toil here captures the sense of diligent endeavor and the willingness to endure hardship in pursuit of achievement.
On'yomi
Kun'yomi
つと.める