bloom has 12 distinct synonyms spread across 7 of its 7 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 organic process of bearing flowers
“you will stop all bloom if you let the flowers go to seed”
reproductive organ of angiosperm plants especially one having showy or colorful parts
a rosy color (especially in the cheeks) taken as a sign of good health
the period of greatest prosperity or productivity
Synonyms, antonyms and the broader and narrower relations for bloom come from Princeton University’s WordNet. Full sources and licences.