tune has 7 distinct synonyms spread across 3 of its 5 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 untune.
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 succession of notes forming a distinctive sequence
“she was humming an air from Beethoven”
Synonyms, antonyms and the broader and narrower relations for tune come from Princeton University’s WordNet. Full sources and licences.
the property of producing accurately a note of a given pitch
“he cannot sing in tune”
the adjustment of a radio receiver or other circuit to a required frequency