rhetoric has 8 distinct synonyms spread across 2 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. 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.
using language effectively to please or persuade
high-flown style; excessive use of verbal ornamentation
“the grandiosity of his prose”
study of the technique and rules for using language effectively (especially in public speaking)
Synonyms, antonyms and the broader and narrower relations for rhetoric come from Princeton University’s WordNet. Full sources and licences.