5 Cain, murderer, from the Bible. Can, prison, US word, with I, one, inside.
16 Double definition - sporting terminology ( the number 10 in something/some sport must be called the Stand-Off and it also means stalemate, deadlock etc.)
Thanks, Jono. I'd heard the word before, probably in a tv commentary (going on in the background), so I knew it was real... I just didn't know the sport!