Antonyms for the phrase "catching flies" can be described as energetic, lively, or alert. If a person is not catching flies, they are actively engaged in something, fully awake, and aware of their surroundings. Antonyms for "catching flies" can include being sharp, quick, and responsive. A person who is lagging, drowsy, or lethargic would not be used as an antonym, as they would be more similar to the original phrase's definition. Antonyms to "catching flies" often involve movement and alertness in a given situation, while "catching flies" implies a state of boredom or lack of focus.