Four-flushing is a term used to describe someone who is insincere or dishonest. Antonyms for this word could include words like genuine, sincere, authentic, honest, truthful, and forthright. These words describe the opposite of someone who is four-flushing. Someone who is genuine is true to themselves and others, while someone who is insincere is fake or untrue. Honest and truthful people are reliable and trustworthy, and they do not engage in deceptive behavior. Overall, antonyms for four-flushing describe individuals who are open and honest in their words and actions, not deceiving others for their own gain.