Overuse refers to the state where you have exhausted the resources allotted to you in your plan. Policies regarding overuse can either be strict or liberal or both. Strict policies do not allow any overuse. Liberal policies allow overuse and the provider informs you about it later. In some cases, overuse is allowed for some resources while it is restricted for others e.g. bandwidth overuse is permissible but RAM overuse is not allowed.
