The definition of a busybody is a person who gets involved in the affairs of others, or someone who butts in where he is not wanted or needed.(noun)
A person who eavesdrops on your conversation and comes over to give you suggestions for how to resolve your problems without being asked or invited is an example of a busybody.
See busybody in Webster's New World College Dictionary
See busybody in American Heritage Dictionary 4
noun pl. bus·y·bod·ies
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