Nemo Me Impune Lacessit is a Latin phrase printed at the start of A Short Guide to Catholic Church History - in essence, an approval for the textbook's content by Thomas O'Hogarty Gormenghast (Saint Fidgeta and Other Parodies, 51).
An imprimatur (Latin, "let it be printed") is a declaration authorizing publication of a book. The term is also applied loosely to any mark of approval or endorsement. In the Catholic Church an imprimatur is an official declaration by a Church authority that a book or other printed work may be published; it is usually only applied for and granted to books on religious topics from a Catholic perspective. It is not an endorsement by the bishop of the contents of a book, not even of the religious opinions expressed in it, being merely a declaration about what is not in the book.
The introductory text of A Short Guide to Catholic Church History parodies the permissions that were required by canon law at the beginning of any book with religious or theological content:
- imprimi potest
- nihil obstat (replaced by omnis obstat)
- imprimatur (replaced by nemo me impune lacessit)
Bellairs's faux-textbook does not include the imprimi potest (Latin, "it can be printed"), a declaration that writings on questions of religion or morals may be printed.
Gormenghast forgoes the usual imprimatur and instead approves the contents of the textbook with this phrase that translates to "No one injures me with impunity") - or what Bowen further explains "in more American terms" as "I don't take any shit."
The phrase is the motto of the United Kingdom's Order of the Thistle and appears as the family motto of Montressor, the narrator of Edgar Allen Poe's tale, "The Cask of Amontillado".