Someone who looks up "stupid" in the Urban Dictionary.

A few weeks ago, no one had “cheugy” in their vocabulary . Now everything is saturated with the word. It’s in our heads. It’s in our homes. Everyone is asking: “Am I cheugy? Am I a basic ass bitch? Am I GUILTY of being cheugy?”

The proliferation of cheugy in the mainstream discourse can only be attributed to one source: mental terror. It’s an orchestrated psychological trap to make you question your tastes and interests in the eyes of others.

You are not a cheug. YOU’RE PERFECT!!!!

It is very suspicious that the cheugy mascot is a Minion, a literal cyclops, a deformed
yellow panopticon in overalls ... do not let the all-seeing eye to control you. Be vigilant. Resist cheugy psyops.

an adjective to best describe the average person

Here are some ways of calling someone 'stupid':
A Few Clowns Short of a Circus
A Few Fries Short of a Happy Meal
An Experiment in Artificial Stupidity
A Few Beers Short of a Six-Pack
Dumber Than a Box of Hair
A Few Peas Short of a Casserole
Doesn't Have All Her Cornflakes in One Box
The Wheel's Spinning, But the Hamsters Dead
One Fruit Loop Shy of a Full Bowl
One Taco Short of a Combination Plate
A Few Feathers Short of a Whole Duck
All Foam, No Beer
The Cheese Slid Off Her Cracker
Body by Fisher, Brains by Mattel
Couldn't Pour Water Out of a Boot With Instructions on the Heel
He Fell Out of the Stupid Tree and Hit Every Branch on the Way Down
An Intellect Rivaled Only by Garden Tools
As Smart as Bait
Chimney's Clogged
Doesn't Have All His Dogs on One Leash
Doesn't Know Much but Leads the League in Nostril Hair
Elevator Doesn't Go All the Way to the Top Floor
Forgot to Pay Her Brain Bill
Her Sewing Machine's Out of Thread
His Antenna Doesn't Pick Up All the Channels
His Belt Doesn't Go Through All the Loops
If She Had Another Brain, It Would be Lonely
Missing a Few Buttons on His Remote Control
No Grain in the Silo
Proof That Evolution Can Go in Reverse
Receiver is off the Hook
Several Nuts Short of a Full Pouch
Skylight Leaks a Little
Slinky's Kinked
Surfing in Nebraska
Too Much Yardage Between the Goal Posts
Not the Sharpest Knife in the Drawer
The Lights are on, but Nobody's Home
24 Cents Short of a Quarter

Takes the place of "very" or similar adjective. Can also mean "a lot" or "intense".

One word. Trump.

Someone of low intelligence.