pesticide; repellent; eliminator; -cide
A substance used to drive away or exterminate pests. Often appears as a suffix in product names (e.g., 虫駆除剤, ゴキブリ駆除剤).
This pesticide works on cockroaches.
I spread ant repellent in the garden.
Compound of 駆除 (kujo, 'extermination') + 剤 (zai, 'agent, chemical'). The reading is standard on'yomi.