The term "omnishambles" is a relatively new addition to the English language, and it refers to a situation that is characterized by complete chaos and disorder. If you're looking for synonyms for this word, there are quite a few options to choose from. Some possible choices might include "clusterf***," "fiasco," "catastrophe," "debacle," "disaster," "chaos," "mayhem," "mess," and "shambles." All of these words are intended to convey the same sense of confusion and disorder that the term "omnishambles" does, so if you're looking to mix up your vocabulary a bit, any of these words would be a good choice.