un·voiced 
/ˌʌnˈvoɪst/ adjective
/ˌʌnˈvoɪst/ adjective 1 : not expressed in spoken words
▪ They nodded their unvoiced [=unspoken] agreement. 2 linguistics, of a speech sound : made without vibrating your vocal cords
▪ The “th” in the word “thing” is unvoiced.
▪ They nodded their unvoiced [=unspoken] agreement.
▪ The “th” in the word “thing” is unvoiced.
