1. A person (often a female) who does something or acts in a way that is so obviously annoying that not calling it out would be a crime.
2. Someone you disagree with. A person who listens to the Jonas Brothers while on a road trip with people who actually have good taste in music.
3. A proclomation of something terrible, i.e "ho-bag! i just dropped my ice cream!" When in the presence of small children, synonyms such as CRAYON-bag, MARKER-bag or HORTON-HEARS-A-WHO-bag work just as well (the latter is a personal favorite)
Friend 1: "He kept hugging his ex at this concert we went to."