“Neuroqueer” recognises that historically and politically, the attempt to eliminate and marginalise LGBTQ+ identities has been deeply connected to the attempt to eliminate and marginalise neurological difference; likewise, the term appeals to people whose experiences as gender, sexual, and relationship minorities are deeply connected to their experiences as neurological minorities. The people who bullied me at school would call me “gay,” “freak,” and “boff” all in the same breath, so I embrace “neuroqueer” as a way of taking back their labels, and critiquing the social and historical conditions that led them to see me as a valid target for abuse.
If to "queer" something means to upset the social norms that brought it into being (particularly cisheteronormativity) then to "neuroqueer" is to upset the social norms around our own minds (particularly neuronormativity). To identify as neuroqueer is to identify oneself with such a political movement.
One benefit of this term is that it promps me to recognise that there is significant continuity and overlap between marginalisation based on neurotype or cognitive style, and marginalisation based on gender or orientation. When children are punished for showing neurodivergent traits, there is a heavily gendered dimension to the way their traits are perceived. When adults recognise their own neurodivergence and learn to embrace it, they often also recognise that they do not identify with gender in the cisheteronormative way. These are only two examples of a multidimensional issue that unfolds in many fascinating ways.
I learned this term from M. Remi Yergeau's Authoring Autism, but it seems to have been coined by Nick Walker and Athena Lynn Michaels-Dillon. All three of them have collaborated in bringing together a body of work exploring the concept. Nick walker has expressed that she finds many common understandings of the term to be a bit limited and simplistic. I suppose a definition that I often hear is "your gender and/or orientation is non-normative in a way that is inseparable from your neurodivergence", and that's often how I use the word. But the vital political work of neuroqueering should not be lost just so that we get a tidier adjective to apply to ourselves.
Elsewhere: Neuroqueer.com (Nick Walker) 
Person: Nick Walker
Person: Athena Lynn Michaels-Dillon
Person: M. Remi Yergeau
Year: 2015