There are plenty of different phrases and terms that can be used as synonyms for "weed killer". Some of the most common include herbicide, vegetation control, weed control, and plant killer. Other alternatives might include terms like pesticide, insecticide, or fungicide, depending on the specific purpose of the product. Some brands might also use marketing-friendly phrases like "weed be gone" or "weed stopper" to describe the effects of their products. Ultimately, the goal of all of these different terms and phrases is to communicate the same basic idea, which is the ability to get rid of or prevent unwanted plant growth.