rue has 6 distinct synonyms spread across 3 of its 5 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.
European strong-scented perennial herb with grey-green bitter-tasting leaves; an irritant similar to poison ivy
leaves sometimes used for flavoring fruit or claret cup but should be used with great caution: can cause irritation like poison ivy
sadness associated with some wrong done or some disappointment
“he drank to drown his sorrows”
Synonyms, antonyms and the broader and narrower relations for rue come from Princeton University’s WordNet. Full sources and licences.