non-proliferation has 1 distinct synonym spread across 1 of its 1 sense. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is proliferation.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
the prevention of something increasing or spreading (especially the prevention of an increase in the number of countries possessing nuclear weapons)
“they protested that the nonproliferation treaty was just a plot to maintain the hegemony of those who already had nuclear weapons”
Synonyms, antonyms and the broader and narrower relations for non-proliferation come from Princeton University’s WordNet. Full sources and licences.