WordNet records no synonym and no antonym for versification. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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 metrical adaptation of something (e.g., of a prose text)
the form or metrical composition of a poem
the art or practice of writing verse
Synonyms, antonyms and the broader and narrower relations for versification come from Princeton University’s WordNet. Full sources and licences.