Stagger, be unsteady (6)
I believe the answer is:
totter
This clue is a double definition.
'stagger' is the first definition.
(I've seen this before)
'be unsteady' is the second definition.
(I've seen this in another clue)
(Other definitions for totter that I've seen before include "Waver and threaten to fall" , "Scrap dealer" , "Be unsteady on one's feet" , "rock" , "I add" .)