The word sassily means to speak or behave in a cheeky or rude manner. Some synonyms for this word could be impudently, brashly, insolently, brazenly, or saucily. Other words that could be used to describe a similar attitude or behavior include snarky, sassy, snappy, or flippant. These words are often used to describe someone who is being overly confident or brash in their speech or behavior, and they may be seen as disrespectful or even confrontational. Despite this, many people use these words as a way to express humor and wit in their communication style.