If someone kicks the bucket they die, or pass away. It is an informal expression but is used quite frequently in English.
Be careful when you use this expression as it is quite informal. Use it to talk about people you don't know.
Don't use this expression to talk about a death if someone is upset or grieving.
Did you hear about old Mr Jones? He recently kicked the bucket.
Before I kick the bucket I want to travel around the world and see as many places as I can
Here's one more English expression for you to learn.
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