The phrase "most unoffending" means harmless or not causing any offense. Its antonyms, however, would be related to causing harm, offense or disgust. Some of the antonyms for "most unoffending" are: offensive, aggressive, rude, impolite, insensitive, obnoxious, unpleasant, harmful, violent, threatening, hurtful and annoying. These words convey a negative tone and highlight actions that might cause damage, injury or hurt. It is important to be aware of these antonyms to be able to accurately express oneself and to understand the context of a conversation, especially when discussing sensitive or controversial topics.