The term 'Outback Jumper' is a type of clothing worn in Australia. It is a loose-fitting, lightweight garment made from wool or cotton, usually with a hood and pockets. The term 'ROO' is an abbreviation for kangaroo, which is an iconic animal native to Australia. Therefore, the crossword solution for the term 'Outback Jumper' is ROO, as it is a fitting representation of the garment's Australian origin.