The antonyms for "busting open" include words like closing, sealing, locking, fastening, securing, and tightening. These antonyms belong to the category of words that indicate the act of keeping something closed or contained. They are opposite in meaning to "busting open," which implies an action of breaking, tearing, or ripping something apart. When we use antonyms for "busting open," we are talking about keeping things safe, secured, or private. For instance, one can use a lock to secure a door, seal a package to keep its content safe, or tighten a lid to prevent a container from leaking. Overall, antonyms for "busting open" are words that promote safety, containment, and control.