mute vs unspoken

mute is a noun but unspoken is not a noun.

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

As adjectives, mute and unspoken are synonyms defined as:

Other synonyms of mute include silent, tongueless, wordless.

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

mute (adjective)	unspoken (adjective)
expressed without speech	not made explicit
unable to speak because of hereditary deafness	expressed without speech

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