The term "Smooth Brain" refers to someone unintelligent, or an action that could be classified as unintelligent. Neuroscientists believe that the more folds your brain has, the more surface area neurons have, thus, leading to higher intelligence. However, without these folds, there won't be as large of a surface area for your neurons, which leads to idiocy, or Smooth Brainedness.
"This buttery smooth brained idiot stuck a goddamn fork in the power outlet."
"That was the most smooth brained sentence I've ever stumbled across in my 25 years on this planet."
"That was the most smooth brained sentence I've ever stumbled across in my 25 years on this planet."
by Imagine Being Smooth Brained June 12, 2022

by Γαπδθμ Λφπ Δдялειг April 3, 2021

by The Gruchinator August 18, 2016

by qqquota December 14, 2024

by Hokiepharm January 7, 2021

Similar to the Indonesian slang term "otot polos" with this same meaning, this tongue-in-cheek term referring to Deadpool's poor self-control, particularly in his tendency to swear and act impulsively. This phrase playfully implies that, like smooth muscle tissue, which operates involuntarily, Deadpool's mouth runs on autopilot, often leading to hilariously inappropriate outbursts.
I love how Deadpool is total smooth muscle—his swearing just pops out without a filter, making every scene even more entertaining!
by Emotional Cruiser September 26, 2025

by Lilmamachick August 17, 2018
