Approach as tempest holds speed (5)
I believe the answer is:
haste
'speed' is the definition.
(I know that haste is a type of speed)
'approach as tempest holds' is the wordplay.
'holds' indicates the answer is hidden within the clue.
'HASTE' is hidden within 'approach as tempest'.
(Other definitions for haste that I've seen before include "make speed" , "Urgency of action" , "Overly eager speed" , "impetuosity" , "furious activity" .)