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. perilous-fraught with danger; dangerous waters; a parlous journey on stormy seas; a perilous voyage across the Atlantic in a small boat; the precarious life of an undersea diver; dangerous surgery followed by a touch-and-go recovery.