If your fridge's water dispenser is suddenly shooting out cloudy water, there are a few things that could be causing the problem. First, check to see if the filter needs to be replaced. If it's been more than six months since you last changed the filter, that could be the culprit. You can find replacement filters at most hardware stores.
If replacing the filter doesn't fix the problem, then it's likely that something is blocking the water line. This is usually caused by sediment build-up in the line. To clean it out, disconnect the water line from your fridge and use a small brush or compressed air to clear any obstruction. Once you've done that, reconnect the line and run some water through it until it runs clear again.
If you're still having trouble after trying these two fixes, then you may need to call a professional to come take a look at your fridge.