A chemical agent that destroys unwanted plants (weeds) but not wanted ones (crops etc)(noun)
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Use "weedkiller" in a sentence
"Enjoy, but watch my dad ... he's lethal with the hoe & weedkiller!"
"DuPont initially touted Optimum GAT to farmers as an alternative to them buying seeds equipped with Monsanto's gene for surviving glyphosate, the active ingredient in Monsanto's Roundup weedkiller."
"DuPont's Optimum GAT seeds are genetically modified to grow into soybean plants able to survive exposure to glyphosate-based weedkiller as well as another herbicide called acetolate synthase."