nomination has 2 distinct synonyms spread across 1 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. 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 officially naming a candidate
“the Republican nomination for Governor”
the condition of having been proposed as a suitable candidate for appointment or election
“there was keen competition for the nomination”
Synonyms, antonyms and the broader and narrower relations for nomination come from Princeton University’s WordNet. Full sources and licences.
an address (usually at a political convention) proposing the name of a candidate to run for election
“the nomination was brief and to the point”