See GI shot in prolonged attack (5)
I believe the answer is:
siege
'prolonged attack' is the definition.
(I've seen this in another clue)
'see gi shot' is the wordplay.
'shot' is an anagram indicator.
'see'+'gi'='seegi'
'seegi' anagrammed gives 'SIEGE'.
'in' is the link.
(Other definitions for siege that I've seen before include "Operation to surround and cut off supplies" , "Blockade of a fortified place" , "Persistent attempt to gain" , "Offensive encirclement" , "Operation to capture a fort, for example" .)