polyphonic 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. Its one recorded opposite is monophonic.
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.
of or relating to or characterized by polyphony
“polyphonic traditions of the baroque”
having two or more independent but harmonically related melodic parts sounding together
1 of the 3 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for polyphonic.
Synonyms, antonyms and the broader and narrower relations for polyphonic come from Princeton University’s WordNet. Full sources and licences.