Feeling of uncertainty (5)
'feeling of uncertainty' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for doubt that I've seen before include "One certainly can't have it" , "Be uncertain about or consider unlikely" , "Question the truth or accuracy of" , "Don't be so sure!" , "Have reservations or be uncertain about" .)
(Other definitions for wobble that I've seen before include "Low ebb (anag.)" , "Totter" , "Stand unsteadily, rock a little" , "Sway unsteadily" , "Shake" .)