Going ballistic is a phrase used to describe someone who has become very angry and is losing control. Synonyms for this phrase can vary depending on the context. Some similar phrases include losing one's temper, flying off the handle, flipping out, freaking out, and having a meltdown. All of these phrases depict someone who is no longer in control of their emotions and is reacting with intense anger or frustration. Other synonyms that may be more mild in tone but still describe a person becoming upset include getting agitated, worked up, or irate. Regardless of the specific words used, going ballistic is never a pleasant experience for anyone involved.