"Primary and Non-Contributory" wording is a term in insurance, especially in the context of liability insurance.
"Primary" means that the policy will pay out on a claim before other policies (which are considered "secondary") pay. In other words, if a claim is filed, the primary policy pays first up to its policy limits, and then the secondary policy would pay if the primary policy's limits were exhausted.
"Non-Contributory" means that the primary policy will pay its full policy limits on a claim and will not seek contribution from other policies that also provide coverage.
A policy with Primary and Non-Contributory wording will be the first to pay in the event of a claim and will not seek to share the cost of the claim with other policies.