glasswort has 8 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.
bushy plant of Old World salt marshes and sea beaches having prickly leaves; burned to produce a crude soda ash
fleshy maritime plant having fleshy stems with rudimentary scalelike leaves and small spikes of minute flowers; formerly used in making glass
Synonyms, antonyms and the broader and narrower relations for glasswort come from Princeton University’s WordNet. Full sources and licences.