Ningender (shortened to Nin) is an umbrella term for all genders which are neutral/non-binary in nature (NIN). It can be used as an umbrella term for any genders that are primarily related to a gender that is not masculine or feminine. This includes gender such as neutrois, agender, maverique, and unaligned non-binary genders among others. NIN is not synonymous with non-binary, because, for example, juxera is non-binary but it is feminine in nature, not neutral. It can also be used as a gender on its own, referring to any gender that isn't fully defined by being neutral but is still related to neutralness, or a gender in which neutralness is its defining feature. It's often used by people who cannot narrow down their gender any more than being neutral or non-binary.
The masculine equivalent is mingender. The feminine equivalent is fingender.