I had a Mercury Cougar with the same sound, I replaced the rear stabilizer/sway bar links. They are reasonable inexpensive and are very easy to replace providing you have some experience with working on suspension.
Most likely you need a new strut
a clunk noise over bumps
Yes it is possible. I have a 2001 sentra and recently replaced the front right strut and coil spring. It didn't have a springing sound though, more of a clunk sound when driving over bumps and on turns. The strut was bent and the coil spring broken. Also the sway bars had play. It was safe to drive with play in the bar, but until it got new links put in, it still made the same sound.
You're a clunk-head...
If it is a cruching, squeeky kind of sound you most likely need your rear struts lubed. Minor and inexpensive.
It sounds like a wheel bearing has gone. DO NOT continue to drive until you have had it checked out.
A clunking sound on shifting gears and while driving can be indicative of failed transmission mount. If the condition is always occurring regardless of shift and driving on level surfaces an internal automatic transmission mechanical condition is possible also.
You will feel a definite high speed vibration when driving. And you'll hear a very distinctive "clunk" when shifting from drive to reverse or visa-versa.
Jammed brakes...get them opened up and cleaned if the cars ben idle for a while...or could be the CV joints,try regreasing them
Please ask this question again describing the noise (clunk/rattle/squeak/rub/rumble/groan/usw.) and type of vehicle (year/make/model/notcolor.)
Can be a loose shock, or loose suspension parts. Can also be loose exhaust system parts. I had a car that made a front-end knocking sound on bumps. Any little bump would do it. Turned out to be bad struts.
Check control arm bushings and other suspension parts specifically front swaybar bushings- these were a known problem for Chrysler- your dealer stocks them