Warbler said:

a·the·ism
ˈāTHēˌizəm/Submit
noun
noun: atheism
disbelief or lack of belief in the existence of God or gods.
synonyms: nonbelief, disbelief, unbelief, irreligion, skepticism, doubt, agnosticism; nihilism

ag·nos·tic
aɡˈnästik/Submit
noun
plural noun: agnostics
a person who believes that nothing is known or can be known of the existence or nature of God or of anything beyond material phenomena; a person who claims neither faith nor disbelief in God.
synonyms: skeptic, doubter, doubting Thomas, cynic; More

https://en.wikipedia.org/wiki/Agnostic_atheism