‘虎口’ literally means 'tiger’s mouth'—a compound of 虎 (hǔ, 'tiger') and 口 (kǒu, 'mouth'). While it can refer to the physical mouth of a tiger in zoological or literary contexts, it is far more commonly used figuratively to describe an extremely dangerous or life-threatening situation—akin to being 'in the tiger’s mouth', where escape seems nearly impossible.

This idiom evokes vivid imagery of imminent peril and is often used in narratives about narrow escapes, wartime survival, or high-stakes crises. It appears frequently in historical accounts, martial arts fiction, news reports, and everyday speech when emphasizing extreme risk or a miraculous rescue. Though rooted in animal imagery, its usage is almost always metaphorical in modern Mandarin, carrying strong connotations of urgency, vulnerability, and dramatic deliverance.