Acting beneath oneself is a term that refers to behavior or actions that are beneath one's character, position or status. Antonyms for this term can be described as behaving in a manner that is appropriate, respectful, and reflects one's true self. Some of the most appropriate antonyms for this term include behaving honorably, with dignity, or acting with decorum. Acting confidently, ethically, and professionally can also be seen as antonyms for acting beneath oneself. It is important to remember that how one behaves is a reflection of their character, and it is imperative to act in a manner that is true to oneself and honors their principles, even in challenging circumstances.