The Vietnamese word "kêu cứu" means "to cry for help" or "to call for help." It is used when someone is in a dangerous or difficult situation and needs assistance from others.
In a sentence: "Khi thấy hoả hoạn, cô ấy đã kêu cứu."
In a context: If you are in a situation where someone is drowning, you would shout "kêu cứu!" to alert others that help is needed.