Shart Loaf 

A person who is always being an asshole. A fuck boy. A waste of space.

“Quit being a shart loaf Brian, no one cares about how many bitches you got in your DM’s”

“At least I’m not a shart loaf like you”

Shart Loaf by Smash_the_Pumpkins October 31, 2019

A Few Slices Short of a Loaf of Bread

Somebody who's not quite mentally competent
Similarly you may use the phrase, a few fries short of a happy meal

Weird Bus Dude: Hey wanna be my friend????? (waves spastically)
B: Can't Say I do
S: Well that guy is a few slices short of a loaf of bread!

A Few Slices Short of a Loaf of Bread by Wicked Witch of the West February 28, 2009

Shartload 

not quite a shit load but more than a handfull. you know, a shartload.

Guy1: hello friend, would you like to go to the cinema tonight?
Guy2: no, i am very sorry. i have a shartload of work to do tonight for my seminar tomorrow

Shartload by iridefattwins January 21, 2010