Proceed slowly (4)
I believe the answer is:
plod
'proceed slowly' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for plod that I've seen before include "bluebottle, say" , "Policeman - walk slowly" , "Slow heavy walk" , "Walk slowly with a heavy tread" , "Walk slowly and heavily" .)