Juan Cole gives an excellent definition of "Neoconservative":
Warning: The text below will use the word "Neoconservative." In my lexicon, a Neoconservative is a person from a social group that typically voted Democrat before 1968 but now votes Republican. Neoconservatives include all the white southern Christian denominations, such as the Southern Baptists, that emigrated from the Democratic Party to the Republican Party as a result of the Nixon strategy, as well as the Reagan Democrats (largely working-class Catholics) and Jewish Americans who trod the same path. Neoconservatives tend to be far-right Zionists in the Jabotinsky tradition, whether they are Jews or Christian Zionists, and they are associated with a desire to ethnically cleanse the Palestinians from the West Bank or at least to so circumscribe their existence there as to render them nonentities. The latest Neoconservative to enlist in the cause is Zell Miller, and he typifies the anger, recklessness and disregard for open, democratic values that characterize the movement.
Neoconservatives have gained allies for themselves from some rightwing Realists, such as Dick Cheney and Donald Rumsfeld, to the extent that it may well be that the latter two have been converted to the Neoconservative ideology, which is distinctive because of its historical origins on the right of the old Democratic Party and in some cases in the far left (Christopher Hitchens is another example). Some have attempted to argue that the very term "Neoconservative" is a code word for derogatory attitudes toward Jews. This argument is mere special pleading and a playing of the race cared, however, insofar as only a tiny percentage of American Jews are Neoconservatives, and only a tiny percentage of Neoconservatives are Jews. The Neoconservative movement is an example of what social scientists call cross-cutting cleavages, which are multiple loyalties and identities typical of complex urban political societies.