A slur typically used towards transfeminine people and femboys to imply that they are tricking or "trapping" people into thinking that they are women. Often used in the context of discussions of anime and/or porn (typically hentai).

• Trans Language Primer - "Trap" (https://translanguageprimer.com/trap/)

See also the pages for; transandrophobia, transmisogyny, transphobia, binarism, intersexism, truscum, and gender critical.