The Collaborative International Dictionary of English v.0.48:

Shaky \Shak"y\, a. [Compar. Shakier; superl. Shakiest.]
   1. Shaking or trembling; as, a shaky spot in a marsh; a shaky
      hand. --Thackeray.
      [1913 Webster]

   2. Full of shakes or cracks; cracked; as, shaky timber.
      --Gwilt.
      [1913 Webster]

   3. Easily shaken; tottering; unsound; as, a shaky
      constitution; shaky business credit. [Colloq.]
      [1913 Webster]