Faltering (8)
'faltering' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for unsteady that I've seen before include "Liable to shake" , "Not even" , "not firmly fixed" , "Shaky" , "Not safe" .)
(Other definitions for dithery that I've seen before include "shaking" , "Hesitant" , "Hesitating" , "Quavery" , "Uncertain" .)