diversify has 3 distinct synonyms spread across 2 of its 3 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. Its 2 recorded opposites are specialize, specialise.
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.
spread into new habitats and produce variety or variegate
“The plants on this island diversified”
Synonyms, antonyms and the broader and narrower relations for diversify come from Princeton University’s WordNet. Full sources and licences.
vary in order to spread risk or to expand
“The company diversified”