Gives up prostitute, getting shot in the arm (4-5)
I believe the answer is:
kick-start
'shot in the arm' is the definition.
The definition suggests a verb in its base form which matches the answer.
'gives up prostitute getting' is the wordplay.
'gives up' becomes 'kicks' (kicking is a kind of giving up).
'prostitute' becomes 'tart' (synonyms).
'getting' says to put letters next to each other.
'kicks'+'tart'='KICK START'
Can you help me to learn more?
(Other definitions for kick-start that I've seen before include "Provide an initial impetus" , "Stimulate" , "How to get a motorcycle going" , "Get something going" , "Activate (business or motorbike!)" .)