Cluttered means crowded with things there is no room for. A cluttered desk, cluttered and cramped, a cluttered page.
It describes disorder produced by too much rather than by mess — a cluttered room may be perfectly tidy and still unbearable. In design, a cluttered page has too many elements competing, and removing things is the fix. Note clutter, which is a variant of clotter, meaning to form clots.
1adjectiveclutteredCrowded with things there is no room for.
“Her desk was so cluttered with papers that she couldn't find her keys.”
cluttered is a quality of crowding.