Neo-con stands for "Neoconservatism". Which is an intellectual and political movement in favor of political, economic, and social conservatism. Which first took place in opposition to the perceived liberalism of the 1960s.

According to wikipedia... a "neo-con" was a new comer to conservative thinking that contributed new ideas in America's response to the Cold War (i.e. 60's thru 80's). They influenced Reagan's administration, and many of the "neo-cons" of that era, have returned in George W. Bush's administration. The term was first used after WWII, and always has refered to new-comers, or more accurately, converts to conservative thinking. http://en.wikipedia.org/wiki/Neoconservative

It seems that it is almost impossable to define Neo-Cons because everyone has there own biased on it. I read in the book "Neo-Con Reader" that they are very fond of Bush W. and they think of him as THE Neo-Con prez.

"The Trotskyist pedigree of neoconservatism is no secret; the original neocon, Irving Kristol, acknowledges it with relish: "I regard myself to have been a young Trostkyite and I have not a single bitter memory." Nor is there any doubt about the influence – one might almost say hegemony – of "former Communists" on the post-war conservative movement. Just read the words of one neocon, Seymour Martin Lipset: From the anti-Stalinists who became conservatives – including James Burnham, Whittaker Chambers, and Irving Kristol – the Right gained a political education and, in some cases, an injection of passion. The ex-radicals brought with them the knowledge that ideological movements must have journals and magazines to articulate their perspectives. In 1955, for example, William F. Buckley, Jr., launched National Review at the urging of Willi Schlamm, a former German Communist. In its early years, National Review was largely written and edited by the Buckley family and a handful of former Communists, Trotskyists, and socialists, such as Burnham and Chambers." So, to answer your question, a neo-con is someone who masquerades as a convserative, but in reality is a socialist that doesn't want to risk the embarassment of being identified as a Fascist.