cottonweed has 2 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.
an American everlasting having foliage with soft wooly hairs and corymbose heads with pearly white bracts
any of various plants of the genus Froelichia found in sandy soils and on rocky slopes in warmer regions of America; grown for their spikes of woolly white flowers
Synonyms, antonyms and the broader and narrower relations for cottonweed come from Princeton University’s WordNet. Full sources and licences.