Muck about Definition 1 of 2Pro Tip 1/3Casual Tone Used in informal situations. Avoid in a professional setting or formal writing. I'll just muck about at the park this afternoon. Pro Tip 2/3Lack of Productivity Suggests not using time effectively. Can imply laziness or procrastination. He mucked about instead of finishing his essay. Pro Tip 3/3Leisurely Context Often refers to relaxed, leisure activities without a specific goal. We spent our holiday mucking about on the beach.