Chief Keegan Share definition Flag A term used to describe urinating in one's back garden, preferably from the back door. 1. "I'm going for a Chief Keegan!" 2. "Are we allowed Chief Keegan in this house?" Chief Keegan by chubbylover87 November 15, 2011 0 0 Get merch Get the Chief Keegan mug. Buy Now — $32.95 See more merch