Genderstrange is a term that is described as 'when no one word can identify the gender, but several terms fit.'
It's similar to pomogender, which is defined as 'a gender that no current labels can describe/fit, or the rejection of labeling it.'
History
The term was coined by Tumblr user Ade on or before September 3, 2015.[1]
Flag
The flag was created by DeviantArt user Pastelmemer on or before September 3, 2015.[2]