From Longman Dictionary of Contemporary Englishweedkillerweed‧kil‧ler /ˈwiːdˌkɪlə $ -ər/ noun [countable, uncountable] DLGpoison used to kill unwanted plants
Examples from the Corpus
weedkiller• But do read the directions carefully to ensure you're using the correct weedkiller in the right way.• I've got enough weedkiller there to finish off half Hereford.• You know the danger in weedkiller, but what about the weeds?• An effective control is to paint each emerging shoot with neat weedkiller.• Presently the old lady came towards him, entered the shed and sniffed knowledgeably at a tin of weedkiller.• Obvious sponsors might be seed merchants or weedkiller manufacturers. 