Crack injection (4)
I believe the answer is:
shot
I believe this is a double definition.
'crack' is the first definition.
(synonyms)
'injection' is the second definition.
(synonyms)
(Other definitions for shot that I've seen before include "Sent a bullet" , "Attempt; photo" , "Goal attempt" , "Small drink; (rocket) launch" , "Ruined; photo" .)