1.People that may differ on social political issues such as welfare but agree that the United States should protect its self interests by any means necessary: diplomacy, assassination, encouraging pro-democracy rebels, war. They can be democrats or republicans and so may differ widely on domestic issues. The label can be used retrospectively as it is a new definition of a previously undefined philosophy.
2.A label people inaccurately use to describe conservatives they don't like. Usually the people that use the label incorrectly also believe in other things like UFO's or that the US attacked itself on 9/11 or that all rich people are evil.
1. Ronald Reagan and John F. Kennedy were neo cons.