Another shot advocate (7)
I believe the answer is:
booster
This might be a double definition.
'another shot' is the first definition.
'booster' can be an answer for 'shot' (thesaurus). I am not certain of the 'another' bit.
'advocate' is the second definition.
(booster is a kind of advocate)
Can you help me to learn more?
(Other definitions for booster that I've seen before include "Additional dose that makes sure the first was effective" , "Space rocket's first stage" , "Supplementary vaccine dose" , "Additional strengthening dose" , "Rocket stage; vaccine" .)