scavenger has 2 distinct synonyms spread across 1 of its 3 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.
a chemical agent that is added to a chemical mixture to counteract the effects of impurities
Synonyms, antonyms and the broader and narrower relations for scavenger come from Princeton University’s WordNet. Full sources and licences.
any animal that feeds on refuse and other decaying organic matter