canon has 1 distinct synonym spread across 1 of its 6 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 rule or especially body of rules or principles generally established as valid and fundamental in a field of art or philosophy
“the neoclassical canon”
a priest who is a member of a cathedral chapter
Synonyms, antonyms and the broader and narrower relations for canon come from Princeton University’s WordNet. Full sources and licences.
a contrapuntal piece of music in which a melody in one part is imitated exactly in other parts
a complete list of saints that have been recognized by the Roman Catholic Church
a collection of books accepted as holy scripture especially the books of the Bible recognized by any Christian church as genuine and inspired