Illusogender is when someone knows they're a certain gender, but experiences a feeling of "fakeness" present, either due to neurodivergency or due to outside pressure, such as from parents, society, etc. These feelings and/or pressures can be part of the gender experience.
Illusogender can be combined with the relevant genders one feels. For example: illusoboy, illusogirl, etc.
Flag
The illusogender flag was designed by pride-color-schemes on Tumblr, as known as Pride-Flags on DeviantArt while DeviantArt user FunCatty chose the colors. The flag was posted on September 27, 2015[1]. The color means are unknown. The flag features the famous "duck or rabbit" illusion.