It's an acronym for Female-Exclusionary Reactionary Transperson. FERTs are overly sensitive, narcissistic, attention-deprived,
sexist people who live in an alternate
reality. They'll get angry at anyone who doesn't
play into their delusions and
will engage into activities like bullying, coercion and harassment, while calling 'transphobia' everything they don't like.
Male FERTs frequently claim that they are the real women, while vandalizing women's facilities, telling feminists to go
kill themselves, demanding women change their language and their self-defence strategies. They believe that other people must validate their supposed identity, and that it has to be done by erasing and silencing women.
Woman: Only women give birth.
FERT: Go
kill yourself nazi bitch! You worthless
piece of shit! F*cking TERF! I've never
seen a more hateful person than you!