Pissed-off is a common slang term used to describe someone feeling angry, frustrated, or irritated. However, there are plenty of alternative words that can be used when describing this particular emotion. Some examples include agitated, irate, furious, incensed, livid, in a rage, seething, and fuming. Other terms, such as annoyed, vexed, and irritated, are less intense but still convey a sense of annoyance or frustration. Ultimately, the choice of synonym will depend on the level of anger being expressed and the context in which the emotion is being felt. Regardless of the word used, it's important to express emotions in a constructive way to avoid unnecessary conflict.