“Cultural Marxism” is the new epithet of choice

I’ve been informed I am a “cultural Marxist”. No idea what that means, but I keep bumping into it. It seems to be a sort of right wing swear word, but I’m jiggered if I can figure out what it means, particularly since I’m not a Marxist and I always took Marxism to be a theory about economics, not culture. If one of youse guys could tell me what it is supposed to mean, who coined it, and why, I’d be beholden to you. If I’m to be cursed as a “cultural Marxist” I should at least have some idea of what my nefarious agenda is.