Miffy is an English word that means out of sorts, annoyed, or in a bad mood. There are various other words that can be used as synonyms for miffy. Such words include irritated, agitated, vexed, exasperated, peeved, irked, disgruntled, displeased, cross, and sour. All of these words share a common thread of frustration or annoyance that makes one feel uncomfortable. Being miffy can result from a variety of reasons, such as feeling misunderstood, being ignored, or simply not getting one's way. Regardless of what makes someone miffy, there are plenty of words to describe this state of being.