1. [adj]  not 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"
2. [adj]  not using the voice; "unvoiced thoughts"; "unvoiced consonants such as `p' and `k' and `s'"
3. [adj]  (linguistics) of speech sounds

UNVOICED is a 8 letter word that starts with U.