"Like blue murder" is a commonly used phrase which means to be very upset, angry or agitated. If you are looking for synonyms for this phrase, there are many options available like "fuming", "enraged", "livid", "furious", "incensed", "infuriated", "irate", "outraged", and "seething". All these words convey a sense of anger or agitation that is similar to the phrase "like blue murder". Depending on the context, you can choose the appropriate synonym to convey the intensity of your emotions. Whatever word you choose, make sure it captures your feelings accurately so that the listener or reader can understand the gravity of the situation.