unbelief

epäuskoisuus An absence (or rejection) of belief, especially religious belief
1526, (w), trans. Bible, Mark VI:

And he coulde there shewe no myracles butt leyd his hondes apon a feawe sicke foolke and healed them. And he merveyled at their unbelefe.

On hands and knees he looked at the empty siding and up at the sunfilled sky with unbelief and despair.

Soon Spinoza was regarded as the standard-bearer for unbelief, even though pervading his carefully-worded writings there is a clear notion of a divine spirit inhabiting the world, and a profound sense of wonder and reverence for mystery.