"Thick as a Brick"

"Thick as a Brick" is a phrase used to describe someone who is perceived as unintelligent or slow to understand. It originates from a humorous, satirical song by the progressive rock band Jethro Tull, which presents an over-the-top, mock-serious story. The phrase plays on the pun that someone with a "thick" skull or head is not very smart. While often used playfully or critically, it emphasizes a lack of insight or comprehension in a person or situation.