Dumb (adjective)

1. Lacking the power of speech.
2. Not able to speak.
3. Lacking intelligence.
4. Not able to express oneself well or clearly.

Origin:

From middle english dom, dum, from old english dumb ("dumb, mute, silent"), from proto-germanic *dumbaz ("dumb, mute"), from proto-indo-european *dʰéh₁mōs ("mute, speechless").

Examples:

1. The child was dumb from birth.
2. The man was dumb with fear.
3. He made a dumb mistake.
4. The dog looked at him with dumb eyes.
5. The actor gave a dumb performance.