Nightmaregender is a term for a person's gender that is connected or related to nightmares, bad dreams, illusions, or any other horrors that happen to be in one's sleep.
Nightmaregender was coined by the user Boredomisdead on December 13th, 2020. It was coined on the same day as Devilgender.
The nightmaregender flag was coined on the same day the term was coined by the same person. The flag has a total of three stripes; Dark red representing nightmares; Dark blue representing the night sky; And the moon and the stars representing the night.
The alternative flag was also coined on the same day with a slight change in meaning. The dark blue represents the night sky, the dark red represents nightmares and illusions, and the light red represents sleep.