MRA - Men Rights Activists. It's not really a pejorative label. I think the notion that it is stems from the habit of feminist screechers to hurl this label at everyone who doesn't kiss their ass, like it's a bad thing.

Basically MRA are kind of people who would complain how they are regularly mugged and how police doesn't give a shit about it because they have certain physical traits.

MGTOW are kind of people who would point out that they aren't going to leave the house at all and usually won't get mugged as a result. Which is technically correct too.