promulgation has 2 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. 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.
a public statement containing information about an event that has happened or is going to happen
“the announcement appeared in the local newspaper”
the official announcement of a new law or ordinance whereby the law or ordinance is put into effect
the formal act of proclaiming; giving public notice
“his promulgation of the policy proved to be premature”
Synonyms, antonyms and the broader and narrower relations for promulgation come from Princeton University’s WordNet. Full sources and licences.