Xynthera is a singular gender identity, just like female, male, juxera, etc. It is a gender that, like juxera, is derived but distinctly separate from womanhood and femininity. In the case of xynthera, however, it is not just derived from femininity; it is also derived from xeninity. Xynthera is a single gender that is derived from both femininity and xeninity, but is a single gender, not a mix of the two, and is still completely unrelated to how xenine people and feminine people experience their (respective) xeninity and femininity.
Xynthera is not a combination of feminine and xenine (xeminine), nor does it describe someone who is multigender who is both fiaspec and xiaspec or has xenogenders. It is a distinctly separate gender from the two: derived from them but experienced as a singular, completely coalesced gender that relates heavily to qualities of femininity described in an entirely xenine way. That experience is core to the gender but is still separate from "standard" femininity and xeninity.
It's important to note that xynthera is a gender, not a gender identity, alignment, modality, etc. Someone who is xynthera would say "I am xynthera" or "I am xyntherine", not "I am a xynthera". Someone can be aligned with being xynthera, but it is not in and of itself an alignment, as it's a complete gender, not just an alignment or quality. Since xynthera is derived yet fully separate and distinct from femininity and xeninity, xynthera people may or may not identify as fiaspec and/or xiaspec.
Moon Symbol
The symbol for xynthera people is a moon because, in nature and in many cultures, the moon is portrayed as being derived from feminine aspects and qualities, but it is still entirely separate from femininity in a way that connects the gender experience to non-standard xeninity, making the moon the perfect symbol for xynthera people.
History
The term xynthera was coined by FANDOM user Reign of the queerios on a blog post on March 11, 2021, along with its masculine and androgyne counterparts.