素质 (sùzhì) means "quality" in the sense of a person's character, caliber, or inner qualities. It is often used to describe mental fortitude, moral character, or overall personal competence. In sports contexts, 心理素质 (xīnlǐ sùzhì) refers specifically to psychological resilience.
这个运动员的心理素质非常强。
zhège yùndòngyuán de xīnlǐ sùzhì fēicháng qiáng.
This athlete has very strong mental resilience.
做老师不仅需要知识,还需要很高的综合素质。
zuò lǎoshī bùjǐn xūyào zhīshi, hái xūyào hěn gāo de zōnghé sùzhì.
Being a teacher requires not only knowledge but also high overall quality.
她觉得一个人的素质比学历更重要。
tā juéde yí gè rén de sùzhì bǐ xuélì gèng zhòngyào.
She thinks a person's character matters more than their degree.