Possible tool used by belligerent European city? (6)
I believe the answer is:
warsaw
'european city?' is the definition.
(capital of Poland)
'possible tool used by belligerent' is the wordplay.
I cannot quite see how this works, but
'tool' could be 'saw' (saw is a kind of tool) and 'saw' is found within the answer.
The remaining letters 'war' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for warsaw that I've seen before include "Capital city on the Vistula" , "Capital of a European Union state" , "1929 international agreement regulating commercial air transport" , "Capital city of Poland" , "European city (with a Convention for commercial flying)" .)