What is the meaning of all-out war?

Answer 1

Nothing's been held back, everything's been thrown at the enemy. When you go 'all-out' with anything, you do pretty much everything.

Another term for all-out war is total war. Basically, all resources that are available are being used in the effort to defeat the enemy.

What might happen in all-out war is citizens will be drafted (required to join the military if they are fit to do so), all military forces are mobilised (including the air force, navy, special forces, etc.) and a country or location is placed under martial law, where the military is in charge.

Answer 2

"An all-out war refers to a conflict where all resources and strategies are used without holding back. It typically involves extensive mobilization of military forces and a total commitment to achieving victory at any cost."