An abbreviation of cisgendered (opposite of "transgender") heterosexual: a person that identifies as the sex they were born as and are attracted to the opposite. Mostly used in social justice circles as an ad hominem attack to people who have to audacity to be born identifying with their birth gender and have an opinion different than theirs/zheirs/xirs.

an insult used on tumblr when you can't accuse someone of doing something wrong.

An abbreviation of cisgendered or cissexual heterosexual: a person that identifies as the sex they were born as, and are attracted to people of the sex opposite of theirs, who are usually also cisgendered or cissexual. Mostly used in social justice circles to describe people commenting on LGBT+ matters when they probably shouldn't be.

Disclaimer: use of labels might be seen as limiting, marginalizing or alienating. Attraction also applies to romantic attraction: heteroromantic, homoromantic, etc.