Final answer:
Napoleon referred to guerrilla war as spineless because it did not follow traditional military tactics and instead relied on asymmetrical warfare.
Step-by-step explanation:
Napoleon referred to guerrilla war as spineless because it deviated from traditional military tactics of large open battles and instead relied on asymmetrical warfare.
In Spain, the guerrillas, or determined weaker forces, targeted French soldiers in ambushes and hit-and-run raids, whittling them down over time. Napoleon's attempts to pacify Spain and defeat the guerrillas were unsuccessful, and his best troops were trapped in a war that did not adhere to his rules.
Overall, the nature of guerrilla warfare in Spain challenged Napoleon's military strategies and resulted in heavy financial costs and casualties for the French forces.