The word "stops up" refers to the act of blocking or obstructing the flow of something. Antonyms for "stops up" include words that denote movement, flow, and continuity. These include terms such as "flowing," "running," "streaming," "gushing," "pouring," "passing," "circulating," and "moving." Additionally, words like "unblocking," "unclogging," "draining," "clearing," or "opening" are also antonyms as they indicate the act of removing an obstruction. Thus, by using these antonyms in language and communication, people can achieve a clearer and more precise expression of meaning, emphasizing the action or inaction in the context.