TAC'IT, adjective [Latin 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, etc.