dumb vs mute

dumb is not a noun while mute is a noun.

Word	Noun	Adjective	Verb	Adverb
dumb	No	Yes	No	No
mute	Yes	Yes	Yes	No

As adjectives, dumb and mute are synonyms defined as:

Other synonyms of dumb include silent.

dumb (noun)	mute (noun)
	a device used to soften the tone of a musical instrument
	a deaf person who is unable to speak

dumb (adjective)	mute (adjective)
slow to learn or understand; lacking intellectual acuity	expressed without speech
unable to speak because of hereditary deafness	unable to speak because of hereditary deafness
temporarily incapable of speaking
lacking the power of human speech

dumb (verb)	mute (verb)
	deaden (a sound or noise), especially by wrapping