A non-binary person is someone who does not identify as either fully male or fully female, including such concepts as being both male and female, a mixture, fluidity, no gender whatsoever, a neutral gender or a gender fully distinct from both, etc.
Tradcons criticize the concept as narcissistic or unintelligible. SJWs often identify as non-binary. 'Queer' relates to the concept of non-binary in that it includes people whose sexual orientation does not possess an exact conventional label to describe them, just like non-binary is in terms of gender.
Many incels find it easier to date bisexual, queer, or non-binary women than straight women. This is because many queer women are more attracted to androgynous/undifferentiated men than masculine men.
Non-binary incels in the media
In 2017 Meredith Talusan of Vice, wrote a piece called "Why Can't My Famous Gender Nonconforming Friends Get Laid?" here.
In 2019 Tom Capon of Gaystarnews ran a piece called "LGBTI incels: what it’s like to be queer when no one will sleep with you", interviewing various people from yourenotalone.co, then called Facebook's Incelistan and Incelistan.net.
The common lexicon used in the trans community to refer to biological sex typically divides people into AMAB/DMAB/CAMAB, or assigned, deemed/designated or coercively assigned male at birth, who may or may not be transfeminine (umbrella term for people who are trans women or trans woman-ish), and AFAB/DFAB/CAFAB, the same but for female, who may or may not be transmasculine (people who are trans men or trans man-ish). Contrary to legend spread by anti-trans feminists, the use of the AGAB and DGAB initialisms were coined by trans women and nonbinary people respectively, as opposed to being terms that were 'stolen from the intersex community'.
The terms IAMAB/IAFAB and FAMAB/FAFAB are used exclusively for intersex people, the latter of which being people who have undergone surgeries or non-consensual hormone therapy in order to fit the molds of biological male or female in a way deemed "acceptable". Expect a non-binary person to know a great deal about intersex issues due to the huge overlap in political goals between the two, and the use of intersexuality to validate pro-trans and pro-nonbinary arguments.
Some non-binary people get very offended when you ask which category they belong to, as the very concept of a non-binary identity is about escaping social use of said categories. This, on the other hand, has led to conflict with trans woman SJWs, who point out that this is often done to evade privilege accusations. Which led to the creation of the even more obscure acronyms TME or transmisogyny-exempt (DFAB people, and presumably DMAB non-binary people who look just normal men) and TMC or transmisogyny-constrained.
Differences between each demographic
DFAB nonbinary people are more likely to be unrealistic SJWs who self-infantilize while employing creepy and artificially exaggerated kawaii aesthetics, otherwise known as the uwu phenomenon or tenderqueers. A great deal of them are not even proper SJWs as they are not exactly aggressive, and instead could be described as more classical bleeding-heart liberals, who believe in showing the other face and condemning all types of negativity.
This phenomenon of soft, childish, naïve and very feminine DFAB non-binary people has led to the stereotype that all nonbinary people are just sufferers of the Not Like Other Girls (NLOG) phenomenon and laid onto a trans identity out of a compulsion to belong somewhere.
Those can be contrasted with more classical tomboy gf-style DFAB non-binary people, transmasculine non-binary people, and DMAB non-binary people, who can be divided into people who vaguely come across as male feminists, unintentional glitterpill subscribers, male lesbians, and trans women in all but name.
DMAB nonbinary people who look like plain cis men carry a certain infamy in the left and within feminist communities for leftbook admin sex pests as well as other creeps and predators who identify that way, either disingenuously or not.
Rivalry with incels inside the trans community
A lot of said trans woman SJWs who hold a deep grudge for cis women and DFAB trans people alike form a unique type of transcel-adjacent community and ideological faction themselves, known as baeddels. These would be trans lesbians who only date trans lesbians because 'everyone else is bent onto their destruction', but who treat cis men rather nicely on the possibility that they are eggs i.e. trans people in denial or closeted and still not transitioning yet.
Attempting to "egg-hatch" unsuspecting people is a known transcel practice that has led to great controversy in LGBT circles, therefore it is easy for non-binary people to evoke the legendary infamy of baeddels in discussions in which they are getting harassed by a trans woman who is perceived as also excessively critical of cis women and/or trans men.
Neurotype and developmental characteristics
Most non-binary people can be broadly divided into those who have autism and/or attention deficit and hyperactivity disorder (ADHD), and those who have borderline personality disorder (BPD) and/or complex post-traumatic stress disorder (C-PTSD), or both, and will have the external physical features associated with the equivalent disorder.
More non-binary people than cis people and "binary trans people" (as conventional trans men and trans women are often labeled) tend towards having rounder faces and big, lively eyes that are shaped flat on the bottom and rounded on the top (like people of Indigenous American descent). In comparison with transexuals and cis homosexuals of their own biological sexes, non-binary people also tend to possess higher voices.
It is possible that non-binarism that presents as extremely mild and barely believable forms of transgenderism is associated with the incapacity to internalize social rules and abstract concepts without criticizing them much, as is the case with autism, or an extreme difficulty to form a persistent identity that maintains coherence through one's lifetime, as is the case with BPD and forms of C-PTSD that present somewhat like it.
Therefore, even if most non-binary people may not present with an issue related to the neurological characteristics associated with people who possess classical transsexual gender dysphoria, they might not necessarily be faking it. As expected, non-binary people who have autism typically show an extreme investment in their identities as such, while non-binary people with borderline may feel terribly hurt about being invalidated by others, as they are more sensitive to social punishment and criticism.