By not materialistic I mean someone who just doesn't have interest in material things for the sake of the value it would give them from their possession, but rather acquires them for their functionality or simply because they like it for them. An example of getting something for for the type of materialistic reasons I'm talking about would be... A Fancy car not solely for the purpose as means to get from point A to B, or comfort or practicality, but rather to show off). Similar to getting a nice house or a phone or watch or anything material.
It's not "spiritual" because such person can NOT be spiritual. Nor is it "ascetic" because it's effortless and comes naturally. No desire of things beyond their practical usage.
There is no "discipline" involved. No if you let yourself go, and became lax, you'd fall back to materialism. The word I'm looking for would describe a person to be not materialistic by nature. Whether they let themselves go or not, it would be unnatural for them to be materialistic. No disciple required. Just no desire to attain material things as a tool to increase their self worth by way of using those goods to gain recognition.
As an anology, if they were offered a Rolls Royce or a 1989 Chevy Caprice (but they can't sell the car they choose or give it away), they'd choose the Chevy Caprice simply because they like it more.