The antonyms for the phrase "bust open" are words that convey the opposite meaning. Some of the words that could be used as antonyms of "bust open" are "close," "shut," "seal," or "lock." These words can be used to describe the action of closing or securing something tightly. For example, instead of "busting open" a door, we could say that we "closed" it. Rather than "busting open" a container, we might "seal" it. Using antonyms helps us to better convey our thoughts by offering a more specific, accurate alternative word choice.