Henry
Autoexreginated
There are actual terms for this that get glossed over in our real world, but are very relevant to a fantasy polytheistic world:
Alatrism - belief that there are gods, but that worship is either undeserved or goes unheeded. Conan the Barbarian could have been described as Alatristic - he almost never prayed to Crom because he believed Crom existed but never heeded his people's prayers.
Dystheism - the belief that the gods exist, but are either not wholly good or possibly evil.
Maltheism - certainty that the gods are outright evil.
Any of these would be appropriate. Even if the gods existed, if you believed their actions not worthy of worship, you might behave in a manner described as atheistic, even if you had evidence that beings who called themselves deities existed and took action in the world.
Alatrism - belief that there are gods, but that worship is either undeserved or goes unheeded. Conan the Barbarian could have been described as Alatristic - he almost never prayed to Crom because he believed Crom existed but never heeded his people's prayers.
Dystheism - the belief that the gods exist, but are either not wholly good or possibly evil.
Maltheism - certainty that the gods are outright evil.
Any of these would be appropriate. Even if the gods existed, if you believed their actions not worthy of worship, you might behave in a manner described as atheistic, even if you had evidence that beings who called themselves deities existed and took action in the world.