Smooth-brain 

A derogatory term used to describe someone after they have done something unintelligent, clumsy, or foolish. This term implies a below average intelligence due to an abnormally shaped brain. The expression is used almost exclusively for criticism.

Dude 1: Hey, did you hear that Mike literally got in an accident with a parked car yesterday!
Dude 2: Ya, I cant believe it. What an absolute smooth-brain.

Smooth-brain by Mike N. Ike April 3, 2019

smooth-brain 

crazemazec#1738

wow, craze is a propa smooth-brain

smooth-brain by Ginju April 13, 2022

Smooth Brain 

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

That fucking smooth brain put his shirt on backwards again...

That smooth brain is dumber than a pile of shit.

Smooth Brain by Tip Tank June 8, 2011

Smooth brain 

A cute brain

J: O, you have a smooth brain
O: Does this mean I have a cute brain?
*L, M, N, O, and P all start laughing*

Smooth brain by Ace the simp May 5, 2023

Smooth Brain 

Opposite of big brain. Smooth brain refers to an idiot or someone dumb. Neuroscientists believe the more folds you have in your brain means the smarter you are. Therefore if you are called smooth brain, you have less folds and therefore dumb.

How did you forget to lock the door? Good move, smooth brain.

You don’t know basic math? Smooth brain 🙄

Smooth Brain by TheoPham September 13, 2019

Smooth Brain 

adj. word to describe people that are slow or stupid

adj. describes unfunny, uncool people that are lame

“Oh look at Marquis, he’s so smooth brained”

Smooth Brain by dirtydikdan October 19, 2021

smooth brain 

smooth brain- it is someone that is an idiot. this means that the more ripples you have on your brain, the smarter you are. So in conclusion, if you got a smooth brain then you are a dumb ass.

1.Jim sucks at chess he is such a smooth brain
2. Jim: HOWDY Y'ALL! Darry: pfft smooth brain Bryson: what a dumbass

smooth brain by yomama.coma December 4, 2020