The Supremes announced that corporations don't have "personal privacy rights" under the Freedom of Information Act. AT&T argued that use of the word "personal" in a statutory exemption must be read with the definition of "person" in another part of the statute, to give corporations the protection from certain FOIA requests.
At page 7 of the slip opinion, the Court shares a nice discussion of words that change meaning when used as nouns or adjectives. For instance, words like "corny," "crabbed" and "cranky" have nothing to do with corn, crustaceans or handles that are used to operate machines. And so, AT&T's argument was dismissed for lack of a real world connection between "personal" and "person." It is a fun english lesson, and at 15 pages, it is mercifully short.
I enjoy the last sentence: "We trust that AT&T will not take it personally." Priceless.