living rock has 3 distinct synonyms spread across 2 of its 2 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.
usually unbranched usually spineless cactus covered with warty tubercles and having magenta flowers and white or green fruit; resembles the related mescal; northeastern Mexico and southwestern United States
highly succulent stemless clump-forming plants with grey-green leaves similar in texture to lumps of granite; South Africa
Synonyms, antonyms and the broader and narrower relations for living rock come from Princeton University’s WordNet. Full sources and licences.