When we describe someone as "like a spoiled brat," we typically mean that they are behaving in a selfish, entitled, and immature way. Some synonyms for this phrase could include "acting entitled," "throwing a tantrum," or "behaving like a child." Other possible descriptions might be "ungrateful," "demanding," or "petulant." The overarching theme of these synonyms is that the person in question is behaving in a way that is unbecoming for an adult and may be causing distress or frustration for those around them. It's important to remember that everyone has bad days and may occasionally act in ways that are less than ideal - but if this behavior becomes a pattern, it may be time to address it head-on.