1. a statement which describes the unfortunate, the sorry, or the lowly, but not as to demean the person. the term "jag bag" is generally used as a term of endearment - a way to let them know they are down, but not out.
2. someone who is doing something unintelligent.
3. by adding -ing can also be used as a verb. "he's jag bagging around." meaning the person is wasting too much time doing something stupid.