- mute, tongueless, unspoken, wordless - expressed without speech; especially because words would be inappropriate or inadequate; "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
Antonym: articulate (indirect, via inarticulate)