Abinary refers to any gender that is completely unrelated to maleness/masculinity or to femaleness/femininity, and is nowhere inbetween, while not necessarily being agender, although agender people may also identify as abinary. An abinary person may feel a strong sense of gender, however that gender is completely unrelated from the binary genders (male or female). Abinary is another term for unaligned non-binary. Unaligned refers to the fact that some non-binary people are "man-aligned" or "woman-aligned" while not being men or women. Unaligned non-binary people are completely separate from these categories.
The abinary flag was created by arco-pluris through the Tumblr blog beyond-mogai-pride-flags on May 18, 2018. The term abinary is combination of the prefix "a" and "binary", to mean "lacking binary". Its first mention was in the midbinary coining post by nothorses (was starmashine), other words popped up such as exterbinary and off-binary.