Generally speaking, a prophet is someone who foretells or predicts future events. These days, this could include people from all walks of life, such as parents who predict their children's futures based on the children's behavior. Even weather forecasters could qualify.
But how does someone become a prophet in the deepest sense of the word? Does an individual simply decide one day that he or she has valuable insights about the future that need to be shared with others, and then start prophesying?
That may describe what motivates some prophets, but not those of Jeremiah's caliber. His prophecies, from the late seventh and early sixth centuries BC, endure to this day in the Holy Bible's Old Testament. A prophet in the Biblical sense, Jeremiah was inspired by God to prophesy events concering the welfare of his people, the children of Israel.