痛哭 means 'to weep bitterly' — a strong, unrestrained expression of deep sorrow, grief, or overwhelming emotion. The first character 痛 (tòng) means 'painful' or 'aching', suggesting emotional or physical anguish, while 哭 (kū) means 'to cry'. Together, they emphasize crying that is intense and heartfelt, often involving sobbing, tears, and visible distress. It’s more dramatic and emotionally charged than simple 哭.

This verb is commonly used in literature, news reports, and spoken Chinese when describing reactions to tragic events — such as losing a loved one, failing an important exam, or witnessing injustice. It implies duration and intensity: someone who 痛哭 may cry for minutes or longer, with shaking shoulders and uncontrollable sobs. While it can appear in formal writing, it's also natural in conversational contexts when expressing genuine, profound sadness.