wob·ble also wab·ble 
(wŏbəl)
(wŏbəl)v. wob·bled, wob·bling, wob·bles also wab·bled or wab·bling or wab·bles
v.intr.
1. To move or rotate with an uneven or rocking motion or unsteadily from side to side.
2. To tremble or quaver: The child's voice wobbled with emotion.
3. To waver or vacillate in one's opinions or feelings.
v.tr.
To cause to wobble.
n.
1. The act or an instance of wobbling; unsteady motion.
2. A tremulous, uncertain tone or sound: a vocal wobble.
[Probably from Low German wabbeln; see webh- in the Appendix of Indo-European roots.]
wobbler n.