Smooth brain

A derogatory term used to describe an individual perceived as lacking intelligence and exhibiting quickness to anger. The term is inspired by the koala, a mammal known for its aggressive behavior and cognitive limitations. Despite having a diet exclusively consisting of eucalyptus leaves, a koala might starve if presented with pre-picked eucalyptus, underscoring the reference to an extreme lack of problem-solving ability.

She kept arguing that the Earth is flat, and everyone started to realize she might just be a smooth brain.

His blind support for the Republican Party’s climate change denial made him seem like a smooth brain, ignoring overwhelming scientific evidence.