努力 (nǔ lì) means to work hard, to strive, or to make an effort. It can be used as a verb (要努力, need to work hard), an adjective (努力的学生, a hard-working student), or an adverb (努力工作, work diligently). 努 means to exert force and 力 means strength or effort. It is a key word in Mandarin motivational contexts and reflects an important cultural emphasis on diligence and perseverance.