coltsfoot 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.
tufted evergreen perennial herb having spikes of tiny white flowers and glossy green round to heart-shaped leaves that become coppery to maroon or purplish in fall
perennial herb with large rounded leaves resembling a colt's foot and yellow flowers appearing before the leaves do; native to Europe but now nearly cosmopolitan; used medicinally especially formerly
Synonyms, antonyms and the broader and narrower relations for coltsfoot come from Princeton University’s WordNet. Full sources and licences.