The word "bm" is a commonly used abbreviation for the term bowel movement. However, there are several other synonyms you can use to avoid using this informal term in professional or polite company. Some of the most common alternatives include "stool", "feces", "waste", and "excrement". In medical settings, physicians may also use clinical terms such as "intestinal contents" or "digestive output". Ultimately, it's important to choose the appropriate word based on the context and audience, and to avoid language that may be considered vulgar or offensive.