Dumb-Stupid | Commonly Confused Words

Dumb

/dʌm/

Lacking the ability to speak or considered not intelligent.

They can't make us dumber.As for Clyde he was numb and dumb."Henry, don't play dumb with me.

/ˈstjuːpɪd/

Lacking intelligence or common sense

It is a lesson to you, you stupids.The stupidest fellow!' Stupid man!' shouted the Queen.

Dumb originally referred to being unable to speak, while stupid refers to lacking intelligence.
Dumb can be seen as more outdated and historically indicated muteness.
Stupid is used more commonly to describe a lack of mental acuity or poor decisions.
In modern usage, dumb can be a more casual or slang term to describe foolishness.
Remember that stupid implies a stronger judgment about one's intellect or decisions.