The Reccugender flag. 
A simplified version of the Reccugender flag.
Reccugender or recusogender is a term for when one is unsure of their gender, but they know which gender they are not. For example, a reccuboy would be someone who knows they are definitely not a man/boy. Someone who is a reccuboy may identify with a masculine identity however. It is similar to nongender.
Some reccugender individuals may be uncomfortable with the terms "reccuboy" or "reccugirl" because it gives the illusion of implying that they identify as an alternate version of male or female. One who is uncomfortable with these terms may just use the label "reccugender" instead. Some people might just want to use recusogender because of the bad name the original Reccugender has. This gender can be used as a side label or a main gender.
History
Reccugender was coined as a separate term to "recugender," which was a term used by cisgender individuals to try and include themselves in the community. The original term meant being cisgender, but using a different label to "defy it."
The term was recoined by FANDOM User EclipseWatera on the 6th of December 2020. This page is the original resource for the term.
Flag
The flag was also coined by Wiki user EclipseWatera on the same date. The flag consists of eleven stripes fading into each other. The orange is there because it is considered the opposite of blue or cyan. The green is to symbolize the opposite of pink or magenta. And black is to represent the whole ‘rejection’ element of the term. The invert of blue and pink were used because the term ‘opposite’ is to symbolize rejection.
Etymology
The prefix "reccu" comes from the Latin word "recuso" meaning "refuse."