Clue: Spy's licence to eliminate civilians and corrupted leaders — 0-0, say (6)
Answer: CASTLE
Explanation: Definition: 0-0, say
An anagram ('corrupted') of SLTECA ('**S**py's **L**icence **T**o **E**liminate **C**ivilians **A**nd … leaders'), for the chess notation of a king's side CASTLE (queen side is 0-0-0).