[Chromenut]

The list of possibilities is pretty long. Wheel bearings, but they likely won't knock, more of s scrape or screech. CV joint would be my guess. Do you feel any wobble in the steering wheel? When you get up to speed on the highway, then decelerate, as in foot off the gas, do you feel a heavy vibration?

So many things this could be but I'd get someone knowledgeable to look at it rather than keep on driving and it getting worse.