Foot movements. Unsoku is a series of body movements designed to promote good posture and avoidance skills within the Tomiki system of Aikido. The first section of tegatana no kata is comprised of these sorts of movements.
Force created through motion, or the movement of one's center.
Classically, any force created through use of muscle, but I've come across many applications where very little muscle is required to cause kazushi, but the hands and/or arms are still acting independently of the center.
Equilibrium or timing. This includes the timing of the footsteps, the timing of the hands (as in grasping), and the overall speed of the center of gravity moving through space (a tall person may take fewer steps than a short person, for example, but the two travel the same distance in the same time).
Whole body movement, or repositioning. It can be translated as body-management. Tai sabaki is usually used to avoid an attack, such that the receiver of the attack ends up in an advantageous position, (more than just simple evasion), usually in a turning fashion.
Though I had a hard time pinning down a definition for this, it seems to connote the idea of advancing and retreating motion. I've also seen it defined as "displacing the total body as one unit." (Anyone help me out on this one?)
Basically, good posture.
Change or variation. For example, in aikido, we're starting to look at some variations of the basic 8 releases.