Definitions by Calkimchi

Sleep inertia 

A result of not having social commitments that you care about, leading to a lack of fomo which makes you revert to a human's natural state of sleeping for hours on end.

"I slept for 12 hours last night and I'm still tired?"
"Yup probably cause of sleep inertia."

Sleep inertia by Calkimchi September 6, 2015