When there is an unspoken agreement or understanding between people, their behaviour shows that they agree about something or understand it, even though they have never spoken about it.
1. 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
2. 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"