Drive round with zero speed (5)
I believe the answer is:
oomph
'drive' is the definition.
(I've seen this before)
'round with zero speed' is the wordplay.
'round' becomes 'o' (round can mean a round object**).
'with' is a charade indicator (letters next to each other).
'zero' becomes 'o'.
'speed' becomes 'mph' (miles per hour).
'o'+'o'+'mph'='OOMPH'
(Other definitions for oomph that I've seen before include "Enthusiasm - vigour - sex appeal" , "Spirited vigour" , "Dynamism" , "Ginger" , "Sexy, exciting quality" .)