Entry: codicil (n.)
In context: "...Mario Incandenza sways down the steep path to the portcullis in the warm rain and interfaces with Clipperton through the bars and has the attendant hold the intercom-button down for him and personally requests that Clipperton be admitted under a special nonplay codicil to the regulations..."
Definition: Law. A supplement to a will, added by the testator for the purpose of explanation, alteration, or revocation of the original contents.
And more generally:
SNOOT score: 2
Source: Oxford English Dictionary