Hello

I assume you mean the car is moving or bouncing around a lot after a bump?

If so then the first thing to check is the tyre pressures if these are low the car will fell 'wallowly' and not respond sharply to steering input.

The next thing is the condition of the shock absorbers these will deteriorate with time and can need replacing after 40-80K miles depending on how the car has been driven.
To test give each corner of the car a sharp push down and step back, the car should depress once and return in one smooth motion with no 'after wobble' depending on how bad the wobble it may need the shock replacing.

The last thing is the condition of the suspension joints and these too wear out over time and any loose joints or free-play can mean the wheel is moving around more than it should which will also make the car feel loose and uncontrolled.

Best thing to do if you're not going to do the work is find a reputable garage and ask them to give it a quick inspection and talk you through anything they find.