Lethargender

 is a term for having a lack of a gender and a marked lack of enthusiasm about it. One does not care about their gender, and the thought of it is tiring.

Etymology
Comes from “lethargy” meaning “a lack of energy and enthusiasm”.

Definitions

 * A subset of agender in which you know you lack a gender, but you also lack enthusiasm about your gender. you don’t care about it, and it makes you tired just to think about it. . - Mogai-archive, 2015

History
Lethargender was coined by Tumblr user newtrule in 2015.