rise to power 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. 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 attaining or gaining access to a new office or right or position (especially the throne)
“Elizabeth's accession in 1558”
Synonyms, antonyms and the broader and narrower relations for rise to power come from Princeton University’s WordNet. Full sources and licences.