Reverse trap is the exact opposite of a trap; a phrase commonly used in otaku communities to refer to effeminate male characters, who might also dress as a woman.
By this logic, the “reverse trap” is a woman, who is disguising herself as a man and is possessing masculine features.
Alternate ways of referring to these characters are bishōnen (a trap) and bifauxnen (a fake trap, from combining faux with bishōnen).
The term trap in its current sense was created on 4chan in 2004, when people started using the It’s a trap meme featuring Admiral Ackbar to react to effeminate males, disguised as women.
The first definition of “reverse trap” was uploaded to Urban Dictionary in 2008.
During the 2010’s traps and “reverse traps” got taken up by meme communities across the web, with people creating several memes and other content, revolving around the theme.
4chan and Reddit are places, that are especially swarmed with content about anime characters, that are possessing features of the opposite sex.
- Urban Dictionary – Reverse Trap