The authoritative instrument for the distribution of all forms of official IRS tax guidance is the Internal Revenue Bulletin (IRB), a weekly collection of these and other items of general interest to the tax professional community.
perfidy definition: The definition of a perfidy is a deliberate betrayal. (noun) An example of a perfidy is spreading a best friend's secrets all over town....
Use of one of the emblems in order to protect combatants and military equipment with the intent of misleading an adversary, perfidy, is considered a war crime. From Wikipedia