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....
1. Guilty of or characterized by betrayal of confidence or trust; perfidious. 2. Characterized by unforeseen or hidden hazards; dangerous or deceptive: treacherous waters; treacherous footing. treachâ²erÂ·ousÂ·ly adv.