Ad nauseum is a Latin phrase meaning "to sickness." It is often used to describe repetitive behavior or excessive repetition of something. Some synonyms for ad nauseum include excessively, endlessly, repeatedly, over and over again, tirelessly, inordinately, and persistently. Other synonyms include incessantly, without stopping, never-ending, monotonously, tediously, and ceaselessly. When someone uses a phrase or word ad nauseum, it can become tedious and overwhelming for others, which is why it is good to use a variety of synonyms to avoid getting stuck in a particular phrase that may appear boring or tiresome to your audience.