The word "bursted out" is often used to describe a sudden and forceful expression of emotion or action. However, there are many antonyms for this phrase, which can convey different meanings and nuances. Some possible antonyms for "bursted out" include "held back," "restrained," "controlled," "contained," "suppressed," "moderated," and "curbed." These words suggest a deliberate and intentional approach to one's actions, emotions, or reactions, rather than a spontaneous and uncontrollable burst. Using these antonyms can help to convey a more nuanced and complex portrayal of a character or situation, and can create a more varied and interesting tone in writing.