# smooth brain

> English word · Noun

## Definitions
1. A stupid person.
2. Used other than figuratively or idiomatically: see smooth, brain.

## Etymology
Nominalization of smooth-brained, possibly by reference to lissencephaly (a brain abnormality, usually resulting in severe developmental delay, characterized by the surface of the brain being smooth), or simply by reference to the human brain typically being wrinkly.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/smooth-brain