Term Permissions | drupal.org

This module allows taxonomy administrators the ability to restrict setting individual terms on nodes by user or role. This developed out of a need to allow limiting creation of specific newsletters in the SimpleNews module to a user or role. For example, franchise owners can be limited to their own newsletters while managers can have access to all newsletters. However, the module could be applied to other situations where specific terms are considered to be "privileged" terms, such as marking a wiki page as stable or verified.