Where does “anti-pegasister” come from?

anti-pegasister (English) comes from English pegasister, from English sister, from Middle English suster, from Old English sweostor, from Proto-West Germanic *swester — sister.

anti-pegasister (English): An adult female anti-fan of the animated television series My Little Pony Friendship Is Magic

Definitions

  1. An adult female anti-fan of the animated television series My Little Pony Friendship Is Magic

Ancestry of “anti-pegasister”, step by step

anti-pegasister traces back through two separate lines of ancestry.

via English pegasister

StepLanguageWordMeaning
1EnglishpegasisterA female fan of the animated television series...
2EnglishsisterA daughter of the same parents as another person;...
3Middle EnglishsusterA sister or step-sister; a female sibling
4Old Englishsweostorsister
5Proto-West Germanic*swestersister

via English anti

StepLanguageWordMeaning
1EnglishantiOpposed to something; That has a torsion angle...
2Englishanti-Against, hostile to; Contrasting with the norm;...
3Ancient Greekἀντι-anti-, against; like, reminiscent of
4Ancient Greekᾰ̓ντῐ́opposite
Every word from Proto-West Germanic *swester