I'm not entirely sure specifically as it could vary greatly. But generally, a 'fanfiction' about Supergirl and Mon - El might explore a relationship that has elements of abuse in the context of the story created by the fan writer. It could be about power imbalances, emotional abuse, or other complex relationship dynamics within the framework of their characters as known from the Supergirl series.
Well, 'supergirl mon el abusive fanfiction' could potentially be a story where the relationship between Supergirl and Mon - El is portrayed in a rather dark way. It might be that the writer is exploring how their relationship could take a turn for the worse and involve some form of abuse. Maybe it's about how their different powers and personalities clash in a negative way that leads to an abusive situation.
Fanfiction often takes existing characters and puts them in new and different situations. In the case of 'supergirl mon el abusive fanfiction', it may be an exploration of the characters of Supergirl and Mon - El in a more disturbing light. It could be centered around themes such as control, jealousy, or even physical abuse within their relationship. The author might be using this as a way to analyze the characters more deeply or just to create a very different kind of story from the mainstream Supergirl narrative.