"Dillydally" is a term used to describe someone who is wasting time or delaying things unnecessarily. However, there are several antonyms that can be used to describe someone who is not dillydallying such as efficient, prompt, quick, speedy, agile, brisk, expeditious, immediate, instantaneous, and swift. These words are often used to describe people who are highly productive, quick to take action and complete tasks efficiently. If you want to describe someone who is wasting no time, you can use any of these words as an antonym to "dillydally." Using these words will help you describe someone who is not procrastinating but is highly motivated and focused.