Nequent refers to genders, gender identities, gender presentation, gender/pronoun conformity, sexual/romantic/tertiary orientations, sexes, relationship categories, and other related things which are neither LGBTQ+ nor conformant. This means they are not LGBTQ+, but they are also not the "standard" for their category.
There are many clear-cut standards for what gender, gender identity, sex, orientation, and relationships are "supposed" to be in society, and for many of those categories, not meeting that standard would make one LGBTQ+, but there is nuance to everything which means some identities are neither LGBTQ+ nor conformant.
Reasons
The most common reason for terms falling into the nequent category/criteria is that they fit into a category that is either too new or not well known enough to have a "standard" for it. For example, the idea of tertiary attraction has only recently begun to be more explored among variant communities, so there's no societal "standard" for things like tertiary attractions (sensual, queeplatonic, etc.), meaning using those terms aren't conformant because there's no existing standard for those terms to conform to, but they're also not LGBTQ+ because they also technically don't break any standard- there's no standard for them, so they neither live up to nor break a standard, making them neither conformant (living up to a societal standard) nor LGBTQ+ (not living up to the societal standard).
Other reasons an identity may fall into this category are that they may be both conformant and LGBTQ+ simultaneously, they may be a non-LGBTQ category but may still be in the general vicinity of those categories (like some xenogenders and otherkin), among other reasons.
Tertiary Orientations
All tertiary orientations (orientations for forms of attraction other than romantic and sexual attraction) are nequent because there is no "standard" for tertiary attraction forms due to them being only newly named and discussed. There is no standard for orientations like sensual, queerplatonic, aesthetic, alterous, and other tertiary orientations, so having one of those orientations neither meets nor breaks a standard because a standard doesn't exist- so all tertiary orientations (i.e things like pansensual, omniqueerplatonic, etc.).
Tertiary A-Spectrums
Similarly, all tertiary anattractional spectrums are nequent. Just as there is no standard for tertiary orientation, there is no standard for the amount of tertiary attraction one feels, so identities like aplatonic, demisensual, etc. are nequent identities.