cocklebur has 6 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.
any coarse weed of the genus Xanthium having spiny burrs
burdock having heart-shaped leaves found in open woodland, hedgerows and rough grassland of Europe (except extreme N) and Asia Minor; sometimes cultivated for medicinal and culinary use
Synonyms, antonyms and the broader and narrower relations for cocklebur come from Princeton University’s WordNet. Full sources and licences.