Impiousness is the noun built on impious: the quality of lacking respect for religion or God, or behaviour that shows that quality. It is rarer and even more bookish than impiety. Many careful writers still prefer impiety for the same idea; impiousness simply takes the adjective and adds -ness, so it leans toward “the state of being an impious person” rather than toward one named act. You will meet it in older moral writing more than in the street. In ordinary talk, there is almost always a plainer way: lack of respect, or they have no reverence. The meaning is the same family as impious — not playful naughtiness, not general badness, but a missing of holy respect.

不敬神；不虔誠（指這種態度）