Dictionary

Unable to speak; lacking power of speech (kept in "deaf, dumb, and blind").

Example: His younger brother was born dumb, and communicated with sign language.

Silent; unaccompanied by words.

Example: dumb show

(especially of a person) Extremely stupid.

Example: You are so dumb! You don't even know how to make toast!

Pointless, foolish, lacking intellectual content or value.

Example: Brendan had the dumb job of moving boxes from one conveyor belt to another.

To silence.

To make stupid.

To represent as stupid.

To reduce the intellectual demands of.