There are several synonyms for the word "i o u s" which express the same or similar meanings in different contexts or language variations. Some of these synonyms include "debt-laden", "indebted", "owing", "beholden", "owing money", "owing a debt", "owing a favor" and "owing an obligation". Each of these synonyms reflects the debt or obligation that someone has to be paid back or fulfilled in some way. Moreover, they can be used in different scenarios such as financial or personal relationships. So, knowing these synonyms can help you express yourself more effectively and avoid repetition in your writing or conversations.