Bash or jab (4)
I believe the answer is:
shot
I believe this is a double definition.
'bash' is the first definition.
(both can mean an attempt)
'jab' is the second definition.
(both can mean an injection)
'or' is the link.
(Other definitions for shot that I've seen before include "Firing of a gun" , "Small drink of spirits" , "Small drink; photo" , "Fired a gun" , "description of some silk" .)