unsteadiness

noun

1. The quality or condition of being physically unsteady: instability, precariousness, ricketiness, shakiness, unstableness, wobbliness. See flexible/rigid.
2. The quality or condition of being erratic and undependable: insecureness, insecurity, instability, precariousness, shakiness, unstableness, unsureness. See change/persist, strong/weak.

The noun has 2 meanings:

Meaning #1: the quality of not being steady or securely fixed in place
  Antonym: steadiness (meaning #1)

Meaning #2: the quality of being unsteady--varying and irregular
  Antonym: steadiness (meaning #2)