The term 'ARSENAL STUFF' can be broken down into two words, 'ARSENAL' and 'STUFF'. The crossword solution for the term 'ARSENAL STUFF' is 'AMMO', which is an abbreviation for 'AMMUNITION'. AMMUNITION is a type of military equipment used in firearms, such as guns and cannons. It is typically composed of metal casings filled with gunpowder and a projectile, such as a bullet or shell. AMMUNITION is essential for any military ARSENAL, as it is necessary for the operation of firearms.