dumb (Adjective) — Taking more than usual time to learn or understand; lacking intellectual acuity. ex. "dumb officials make some really dumb decisions"
dumb (Adjective) — Temporarily incapable of speaking. ex. "struck dumb"
dumb (Adjective) — Lacking the power of human speech. ex. "dumb animals"
dumb (Adjective) — Unable to speak because of hereditary deafness.
dumb (Adjective) — Devoid of good sense or judgment.
dumb (Verb) — Make simpler and less intellectually challenging (in a negative sense).