Boscoe Share definition Flag A Silly Man who thinks he is undefinable. There by defining himself as the undefinable. This paradox is known as a Boscoe. The Undefinable defined by saying the Undefinable. Thereby becoming a Boscoe. Boscoe by Not Bear March 4, 2008 0 0 Get merch Get the Boscoe mug. Buy Now — $32.95 See more merch