NonSerialized Inherits from Attribute  

The NonSerialized attribute marks a variable to not be serialized.

This way you can keep a variable public and Unity will not attempt to serialize it or show it in the inspector

// p will not be shown in the inspector or serialized
@System.NonSerialized
var p = 5;

// C# Example
class Test {
    // p will not be shown in the inspector or serialized
    [System.NonSerialized]
    public int p = 5;
}