Not sinking (6)
I believe the answer is:
afloat
'not sinking' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for afloat that I've seen before include "Out of debt; at sea" , "Borne on the water" , "On board at sea, on ship" , "Buoyed" , "Buoyant: solvent" .)