apatheism
Apathy towards the existence of a god; belief that the question of the existence of a god is unimportant.
uncountable
[A]patheism is an attitude, not a belief system, and the over-riding fact is that these people are relaxed about religion.
Where it comes from
Reportedly coined in 2001, as a blend of apathy + theism, by author Robert J. Nash.
Adapted from the Wiktionary entry apatheism (CC BY-SA 4.0).