Dilatory means slow, sluggish or delaying action. Its antonyms include quick, expeditious and prompt. Quick refers to the speed of action, while expeditious means prompt and efficient. Prompt denotes a sense of immediate action without delay. Other antonyms of dilatory are swift, hasty, speedy, and brisk. Dilatory actions also suggest procrastination, thus its antonyms include punctual, timely, and early. Punctual refers to being on time, while timely denotes acting within an appropriate time frame. Lastly, early means in advance or ahead of schedule. These antonyms provide a range of words that convey opposite meanings to dilatory.