Themismasculine is a gender that experiences a small amount of attachment to being male or masculine, but is primarily another gender. A themismasculine person feels between 1-49% masculine. It's a subset of demiboy, where the "other part" of one's gender outweighs the masculine part. The other part of one's gender can be any gender or combination of genders. It is similar to libramasculine, but unlike libramasculine, the majority part of one's gender does not necessarily have to be agender.
Themismasculine was coined by Tumblr user neopronouns on April 30, 2020. The flag was released in the same post.