1. To make dirty, contaminate
2. To spoil by making mistakes or using poor judgment, confuse
3. Entangle, block
4. To cause a foul-up, bungle

1. When you mess up a place, you make it dirty or disorganized.
2. When you mess up a situation, you create problems. When you mess up a plan or arrangement, you interfere with it and prevent it from happening as planned. Mess up is similar to screw up.

1. To screw or turn higher.
2. To twist into a strained configuration