Dullard -

is a noun used to describe a person who is perceived as slow-witted, unintelligent, or unimaginative. While it shares a root with the adjective "dull" (meaning boring or lacking excitement), it specifically implies a lack of mental sharpness or intelligence. Key Meanings and Nuances

If you are looking for alternative words, they range from mild to strong insults: dullard

The term dates back to the Middle English period (c. 1440) and is formed by combining "dull" with the pejorative suffix "-ard". Common Synonyms is a noun used to describe a person