voiceless vs unvoiced

voiceless and unvoiced both are adjectives.

Word	Noun	Adjective	Verb	Adverb
voiceless	No	Yes	No	No
unvoiced	No	Yes	No	No

As adjectives, voiceless and unvoiced are synonyms defined as:

Other synonyms of voiceless include hard, surd.

voiceless (adjective)	unvoiced (adjective)
deprived of the rights of citizenship especially the right to vote	produced without vibration of the vocal cords
produced without vibration of the vocal cords	not made explicit
being without sound through injury or illness and thus incapable of all but whispered speech
uttered without voice