(in the Bible) a Hebrew minor prophet. He was called by God to preach in Nineveh, but disobeyed and attempted to escape by sea; in a storm he was thrown overboard as a bringer of bad luck and swallowed by a great fish, only to be saved and finally succeed in his mission

a person who seems to bring bad luck

you do start to wonder if you are a bit of a Jonah, a bit jinxed