The term 'noxious plant' can be summarized as a WEED, which is a plant that is considered to be a nuisance and is often difficult to control. Noxious plants are usually invasive species that can cause harm to the environment, such as by competing with native plants for resources or by introducing toxins into the soil. They can also be a threat to human health, as some noxious plants contain toxins that can cause skin irritation or other health problems.