The runs affected those who do the scouring (7)
I believe the answer is:
hunters
'the runs affected those who do the scouring' is the definition.
I can't judge whether this definition defines the answer.
'the runs affected' is the wordplay.
'affected' indicates anagramming the letters.
'the'+'runs'='theruns'
'theruns' is an anagram of 'HUNTERS'.
Can you help me to learn more?
(Other definitions for hunters that I've seen before include "Searchers" , "Watches" , "More than one rider" .)