Adjectives

(a)unvoiced, voiceless, surd, hardproduced without vibration of the vocal cords“unvoiced consonants such as `p' and `k' and `s'”
(s)unexpressed, unsaid, unstated, unuttered, unverbalized, unverbalised, unvoiced, unspokennot made explicit“the unexpressed terms of the agreement”, “things left unsaid”, “some kind of unspoken agreement”, “his action is clear but his reason remains unstated”