When iam Driving, and turn Corners my Left hand back wheel make a terrible noise.

The noise is getting worse, and i dont know what it is. My Dad says it could be the CV joint(driveshaft imput?). But iam not to sure. It doesnt happen while Accelerating, But it does when deaccelerating. Maybe wheel bearing??? But iam lost and i have only had the car 4weeks.

So Anyhelp would BE AWESOME!!!
Dil