Muteness is a state of refusing to speak, being unable to speak, or silence. The muteness of the audience at a comedy show might indicate that the comedian isn't very funny — although muteness is probably preferable to outright booing.
When it's a result of a physical or psychological condition or injury, you can also call muteness mutism. Both words come from mute and its Latin root mutus, "silent or speechless." In fact, muteness often simply means "silence." The muteness of your typically noisy family at dinner might be uncharacteristic, while the muteness of your meditation group is perfectly ordinary.