よごす
よごす · yogosu · JLPT N2 · verb-godan
to pollute
🛢️ 汚す = 汚 (dirt, stain; water radical 氵) + verb す: make something dirty or stained
Both senses share the idea of a stain: dirt on a surface, or a stain on a reputation. 名を汚す means to disgrace one's name, while 水を汚す means to pollute water.