ketone body has 1 distinct synonym spread across 1 of its 1 sense. 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 ketone that is an intermediate product of the breakdown of fats in the body; any of three compounds (acetoacetic acid, acetone, and/or beta-hydroxybutyric acid) found in excess in blood and urine of persons with metabolic disorders
Synonyms, antonyms and the broader and narrower relations for ketone body come from Princeton University’s WordNet. Full sources and licences.