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”