There are numerous synonyms for the phrase "pisses moan about" that can be used to describe someone who constantly complains or whines. Some examples include bellyaches, grumbles, gripes, fusses, whinges, moans, and groans. These words all convey a sense of dissatisfaction or annoyance with a particular situation or circumstance. When used in conversation or writing, they can provide a more colorful and descriptive way to convey a person's negative attitude. It's important to choose the right synonym based on the context of the statement and the level of intensity or annoyance being conveyed.