logwood has 4 distinct synonyms spread across 1 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.
very hard brown to brownish-red heartwood of a logwood tree; used in preparing a purplish red dye
spiny shrub or small tree of Central America and West Indies having bipinnate leaves and racemes of small bright yellow flowers and yielding a hard brown or brownish-red heartwood used in preparing a black dye
Synonyms, antonyms and the broader and narrower relations for logwood come from Princeton University’s WordNet. Full sources and licences.