This is the 961st most frequent Japanese word.
努力
Effort or hard work.
努力 is used as a noun here, meaning 'effort,' emphasizing sustained application toward a goal.
彼は成功するために努力を続けている。
He continues his efforts to succeed.
努力 is used again as a noun here, now contextualizing as the origin of the outcomes received.
努力の結果が報われた。
The results of the effort were rewarded.
努力 is used in its verbal form via the verb 努力する (to make an effort), showing the action taken to achieve success.