Definition & Meaning of "dickbrained"in English

What is the origin of the term "dickbrained" and how is it used?

Dickbrained is a slang adjective that appeared in mid–20th-century English to describe someone with extremely poor judgment or intelligence. The term combines "dick", a crude word for the penis, with "brain," suggesting that the person thinks with their genitals rather than their head. Literally, it labels someone as guided by sexual impulses or base instincts instead of reason. Historically and today, it is derogatory and vulgar, used to insult or ridicule someone's stupidity, poor decisions, or lack of common sense.