Which Country suffered the most economically as a result of World War 1?

Germany

Explanation:

Germany suffered the most economically not only because it was one of the main centers of the war, resulting in hundreds of thousands of casualties, and millions in material losses, but also because Germany actually lost the war, and was subject to paying expensive war reparations to the victor countries.

These reparations were very hard to pay for the recovering German economy of the post-war period, and it reached a point in which the German government was forced to print large amounts of money in order to meet the reparations expenses. This spiked in hyperinflation, which further ruined the economy of the German people.

the term is einsatzgruppen