Kick the bucket
Idiom meaning: to die (very informal, humorous, euphemistic).
Origin
We do not like the explanation usually given that the phrase evolved from the action of a suicide, who had stood on a bucket to fit the noose of a rope round his neck, and then kicked the bucket away, so that he hanged.
A more likely derivation is that of the East Anglian 'bucket' - a frame in which a newly slaughtered pig is suspended by its heels. The heels might be said to be kicking the bucket; and the pig was dead.The word 'bucket' is not related to cylindrical vessels for holding water. It is supposed that the word derives from the Old French buquet (a balance).
Think twice before using this phrase - it's rather impolite way for talking about smb's death.