‘倒下’ (dǎo xià) is a verb meaning ‘to collapse’ or ‘to fall down suddenly’, typically due to physical weakness, illness, exhaustion, or injury. It emphasizes an involuntary, often dramatic loss of upright posture — not just stepping backward or sitting down, but a complete physical failure to remain standing or conscious. The character 倒 means ‘to topple’ or ‘to fall over’, while 下 means ‘down’; together, they form a compound verb indicating downward motion resulting from loss of control or strength.

This word is commonly used when describing people fainting, soldiers falling in battle, animals collapsing from disease or old age, or even large objects like trees or buildings toppling during disasters. It carries a tone of seriousness and urgency — you wouldn’t use it for someone casually lying down to rest. It’s neutral in register but often appears in medical, news, or narrative contexts where sudden physical failure is central to the event.