Whereas to have “standing privilege” means to always have access to a resource (whether they need or are using them), Zero Standing Privilege (ZSP) describes an identity’s state of having none, or zero access to a resource.
Why is this an important concept?
Think of it like this: if an identity has a standing admin / root access to a production system, that means the entity assuming that identity can perform admin / root operations against that production system.
This is fine when that entity is your IT staff doing their jobs, but is really bad if its a bad actor who has managed to hack their way in.
In the wrong hands, an identity with standing privileged access is a serious threat. But if an identity has zero standing access, with no access permissions bound to it, it posesses no threat at all.