similar to the word sleek, shleek is something that is extremely sleek and deserves some extra swag with an added 'h'.

when you're hungover as shit after a spending a night drunk as a skunk

Shit that's not on Fleek

When someone is being a bitch or a slut / slag . Basically an insult for anything

A fuckboy or complete idiot that doesn't do what you want them to.