Adjectives

(s)mute, tongueless, unspoken, wordless, silentexpressed without speech“a mute appeal”, “a silent curse”, “best grief is tongueless” (Emily Dickinson), “the words stopped at her lips unsounded”, “unspoken grief”, “choking exasperation and wordless shame” (Thomas Wolfe)
(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”