Emily Dickinson Lexicon

TAC'IT, a. [Fr. tacite; L. tacitus, from taceo, to be silent, that is, to stop, or to close. See Tack.]

Silent; implied, but not expressed. Tacit consent is consent by silence, or not interposing an objection. So we say, a tacit agreement or covenant of men to live under a particular government, when no objection or opposition is made; a tacit surrender of a part of our natural rights; a tacit reproach, &c.