utopia has 2 distinct synonyms spread across 1 of its 4 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. Its one recorded opposite is dystopia.
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 book written by Sir Thomas More (1516) describing the perfect society on an imaginary island
ideally perfect state; especially in its social and political and moral aspects
Synonyms, antonyms and the broader and narrower relations for utopia come from Princeton University’s WordNet. Full sources and licences.
a work of fiction describing a utopia