Adjective: When used as an adjective, it means "unable to speak" or "lacking intelligence."
* Example: "The baby was too young to speak, so she remained dumb. "
* Example: "That was a dumb thing to do."
Adverb: When used as an adverb, it means "silently" or "without speaking." This use is considered archaic and is not common today.
* Example: "He walked dumb down the street, his head hung low."
It's important to consider the context of the sentence to determine which part of speech "dumb" is functioning as.