There are many synonyms for the phrase "in a temper," all of which describe a person who is angry or upset. One commonly used synonym is "irate," which refers to a person who is extremely angry or outraged. "Furious" is another synonym for "in a temper," and implies intense anger and rage. "Indignant" can also be used as a synonym, describing a person who is offended or outraged by something perceived as unfair or unjust. Other synonyms for "in a temper" include "livid," "incensed," "enraged" and "infuriated." Whatever the synonym used, these words all describe a state of emotional distress and anger.