decree has 5 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.
decide with authority
“The King decreed that all firstborn males should be killed”
Synonyms, antonyms and the broader and narrower relations for decree come from Princeton University’s WordNet. Full sources and licences.
a legally binding command or decision entered on the court record (as if issued by a court or judge)
“a friend in New Mexico said that the order caused no trouble out there”