Neocon is a term used to describe someone who's not an actual conservative but pretends to be a "new" version of one in order to hijack a conservative movement in part or whole, to redirect it to support the Neocons' agenda.
That definition needs a definition of a Conservative.
Neo-con is used by many in these forums as a general purpose slur towards posters that generally favor a more interventionist policy against our enemies. It has been misused by conflating it with militarist or war hawks. The term was first used to describe former Great Society but also anti-Communist liberal democrats that left the democrats for their dovish pro-communist attitudes. Barry Goldwater, Ronald Reagan and William F Buckley could be called war hawks cold warriors but they weren’t Neo-Cons. The Kristols and James Schlesinger were.