苦难 (kǔ nàn) is a compound noun meaning 'hardship' or 'suffering'—often referring to prolonged, severe, or collective adversity, such as poverty, war, persecution, or deep personal loss. The first character 苦 (kǔ) means 'bitter' and conveys physical or emotional pain; the second 难 (nàn) means 'calamity' or 'disaster', emphasizing difficulty beyond ordinary challenge. Together, they form a weighty, formal term that evokes gravity and endurance—not everyday inconveniences, but life-altering trials.

This word appears frequently in historical narratives, literature, news reports, and speeches about resilience. It carries a solemn, sometimes literary tone and is rarely used in casual conversation. While it can describe individual suffering, it often implies shared or societal hardship—such as national trauma or generational struggle—and is commonly paired with verbs like 经历 (jīnglì, 'to experience'), 承受 (chéngshòu, 'to bear'), or 克服 (kèfú, 'to overcome').