WordNet records no synonym and no antonym for atrazine. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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 synthetic compound derived from triazine that is widely used as an agricultural herbicide
“atrazine is thought to cause cancer and is banned in some European countries”
Synonyms, antonyms and the broader and narrower relations for atrazine come from Princeton University’s WordNet. Full sources and licences.