Political correctness is, in the common parlance, whatever you don't approve of.
Among sophisticates, it stands for claims that one places the concerns of some minority group that feels victimized by discrimination or slurs by a bigger, more powerful, privileged group.
Examples: conservative students and faculty at elite colleges and universities; Christians, English language speakers, prayer in school enthusiasts, and white people.
Conservatives allege that political correctness is a pandering tool to keep its constituents in line between bouts of giving them free stuff. Interestingly, there is a large and well-established vocabulary of conservative, politically correct, speech. In fact, they often use it on themselves to enforce conformity: "movement" conservatives are truer than others; RINOs are Republicans in Name Only. "Cuckservatives" is a new formulation for a multitude of deviations from Reaganism, which, itself, has spawned a thousand different definitions.
Here is a helpful guide to translating conservative talk into standard English: