Anaplastic is a medical term that is often used to describe cancer cells that have lost their normal structure and function. Some synonyms for this word include undifferentiated, dedifferentiated, and poorly differentiated. Undifferentiated cells are those that have not yet developed into their final specialized form, while dedifferentiated cells have lost some of their specialized characteristics. Poorly differentiated cells are those that have lost most, if not all, of their specialized characteristics. Other synonyms for anaplastic include atypical, abnormal, and anomalous. While these terms are not interchangeable with anaplastic, they do share some common characteristics in terms of the abnormal cellular behavior they describe.