Bonn derives from the word 'bint'. It became 'Bonn' when some people pronounced the 'i' in bint like an 'o'. it has since then evolved into BONN.
(it is also the last name of Terri Bonn)
Some random : 'Look at this! I can jump off this and live!'
*he falls, breaking his legs*
Me : 'Oh, you really are a Bonn'