The phrase "steeped in iniquity" is a powerful description of a situation or person that is deeply, fundamentally corrupt. However, there are many other synonyms that can be used to convey a similar sense of moral depravity or wickedness. For example, you might describe someone as "smothered in sin," "saturated with evil," "immersed in immorality," "drenched in corruption," or "soaked in vice." Each of these phrases communicates a strong sense of wrongdoing and moral decay, and can be used effectively in a variety of contexts, from describing a corrupt government to criticizing an individual's actions.