The Warsaw Pact, for example, left with nothing in years gone by (4)
I believe the answer is:
bloc
'the warsaw' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bloc that I've seen before include "Political or economic confederation" , "Alliance of nations" , "Combination of parties or countries" , "A number of countries" , "Group of allied nations" .)