General Synonyms:
* Mess
* Disorder
* Chaos
* Disarray
* Confusion
* Jumble
* Tangle
* Heap
* Litter
* Rubbish
More Specific Synonyms:
* For physical objects:
* Stuff: Informal and often refers to a large amount of random items.
* Junk: Implies items are useless or unwanted.
* Bric-a-brac: Refers to small decorative items.
* For information:
* Overload: Too much information.
* Confusion: Lack of clarity or order.
* Noise: Distracting or irrelevant information.
The best synonym for "clutter" will depend on the specific context and the nuance you wish to convey.