Nunday
A nunday is a day of the week that feels non-existent and wasted. A day could feel like a nunday due to the weather being terrible or nothing exciting happening to give you any motivation to do anything productive.
Had a proper nunday today
Nunday
a day that comes after Sunday, an extra day added to the weekend, perfered as doing nothing all day.
"Ugh guys I'm having a nunday. I'm just gonna rest."