意志 (yì zhì) is a compound noun meaning 'willpower' or 'determination' — the inner mental strength to persist toward a goal despite difficulty, fatigue, or temptation. The first character 意 (yì) means 'thought', 'intention', or 'idea', while 志 (zhì) means 'aspiration', 'resolve', or 'ambition'. Together, they convey the idea of a focused, sustained intention backed by purposeful commitment — not just a passing wish, but a firm, conscious decision to act and endure.

This word is commonly used in contexts involving self-discipline, personal growth, recovery from illness, athletic training, academic study, or moral perseverance. It carries a formal, slightly literary tone and often appears in motivational speeches, psychological discussions, or written descriptions of character. While it can be used in everyday speech, it’s less common in casual conversation than simpler terms like 决心 (juéxīn, 'determination') or 坚持 (jiānchí, 'persistence').