stone has 15 distinct synonyms spread across 12 of its 16 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.
building material consisting of a piece of rock hewn in a definite shape for a special purpose
“he wanted a special stone to mark the site”
material consisting of the aggregate of minerals like those making up the Earth's crust
“that mountain is solid rock”
a crystalline rock that can be cut and polished for jewelry
“he had the gem set in a ring for his wife”
an avoirdupois unit used to measure the weight of a human body; equal to 14 pounds
“a heavy chap who must have weighed more than twenty stone”
the hard inner (usually woody) layer of the pericarp of some fruits (as peaches or plums or cherries or olives) that contains the seed
“you should remove the stones from prunes before cooking”
United States jurist who was named chief justice of the United States Supreme Court in 1941 by Franklin D. Roosevelt (1872-1946)
United States journalist who advocated liberal causes (1907-1989)
United States jurist who served on the United States Supreme Court as chief justice (1872-1946)
a lack of feeling or expression or movement
“he must have a heart of stone”
1 of the 16 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for stone.
Synonyms, antonyms and the broader and narrower relations for stone come from Princeton University’s WordNet. Full sources and licences.