magnification has 4 distinct synonyms spread across 2 of its 4 senses. 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. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
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 act of expanding something in apparent size
the ratio of the size of an image to the size of the object
making to seem more important than it really is
Synonyms, antonyms and the broader and narrower relations for magnification come from Princeton University’s WordNet. Full sources and licences.