Sentence:  It constrained governments, businesses and labour unions to collaborate in planning increased rates of output and the conditions likely to facilitate them. And above all, it blocked any return to the temptations that had so <WSD>stymied</WSD> the inter-war economy: under-production, mutually destructive protectionism, and a collapse of trade. 
Meaning of the word marked with <WSD> tags:  To thwart or stump; to cause to fail or to leave hopelessly puzzled, confused, or stuck.