Scour island for shooter (8)
I believe the answer is:
rifleman
'shooter' is the definition.
(thesaurus)
'scour island' is the wordplay.
'scour' becomes 'rifle' (both can mean to hunt through something).
'island' becomes 'man' (Man is an example).
'rifle'+'man'='RIFLEMAN'
'for' acts as a link.
(Other definitions for rifleman that I've seen before include "Armed soldier" , "Soldier - crack shot?" , "British private soldier - New Zealand songbird" , "Nil frame for a member of the infantry" , "Soldier carrying gun" .)