Kick start hard after stall (5)
I believe the answer is:
booth
'stall' is the definition.
('booth' can be a synonym of 'stall')
'kick start hard after' is the wordplay.
'kick' becomes 'boot' (booting is a kind of kicking).
'start' says to take the initial letters.
'after' says to put letters next to each other.
The initial letter of 'hard' is 'h'.
'boot'+'h'='BOOTH'
(Other definitions for booth that I've seen before include "Killer of president" , "compartment for voting" , "Stall at fair or market" , "Army leader" , "Stand < and stall" .)