Voidsexual is an ace-spec orientation where one's orientation feels hollow or it feels like a void where one's sexuality should be. It is similar to the difference between agender and gendervoid. An asexual person may also feel as though they never had a sexual orientation in the first place, however a voidsexual person may feel like there is a place where a sexuality would or should be but isn't.
The romantic equivalent is voidromantic.
History
Voidsexual and voidromantic were coined on or before February 17, 2015 by Tumblr user Y0suke through MOGAI-Archive[1].