When you jumble something, you throw a bunch of items haphazardly together. For example, many people jumble many random things in a kitchen junk drawer.
Use the verb jumble to describe what happens when you scramble or mix things up. Some kids, for example, jumble their Lego toys together in a big bin, while others like to sort the pieces by color or size. You can call the mix of items itself a jumble too. In the early 1500s, jumble meant "to move confusedly," and it was probably modeled on stumble. Later that century, it came to mean "mix or confuse."