I have developed such effective sea legs that the solid ground feels unstable.

Like most trucks, this one leans in turns, but doesn't feel unstable.

At highway speeds this fishtailing can make a car feel unstable.

Has your knee given out, buckled, or felt unstable after an injury?

The knee does not feel unstable or give out during activity.

The joint may feel unstable or give out during activity.

The knee feels unstable or gives out at certain times.

There is a great deal of body roll, but the car does not feel unstable.

Has your hip felt loose or unstable off and on for 1 week?

Yet in his hands this dynamic feels unstable and mystifying.