The word "male ass" is a crude and disrespectful term used to refer to a man's buttocks. There are various synonyms which can be used in its place, which are more appropriate and polite. Some of these synonyms include "rear end," "buttocks," "derriere," "bum," "backside," or "behind." Each of these terms allows individuals to refer to the same physical part of the body in a more respectful and professional way. It is essential to consider the context and audience when choosing to use these different terms to ensure that the language being used is respectful and does not offend anyone.