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Clutter is stuck energy. The word "clutter" derives from the Middle English word "clotter," which means to coagulate - and that's about as stuck as you can get.

Karen Kingston (2016). “Clear Your Clutter with Feng Shui (Revised and Updated): Free Yourself from Physical, Mental, Emotional, and Spiritual Clutter Forever”, p.11, Harmony
Clutter is stuck energy. The word clutter derives from the Middle English word clotter, which means to coagulate - and that's about as stuck as you can get.