Justify sabre-rattling diatribe? (7)
I believe the answer is:
warrant
'justify' is the definition.
(synonyms)
'sabre-rattling diatribe?' is the wordplay.
'sabre-rattling' becomes 'war' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'diatribe?' becomes 'rant' (I've seen this in other clues).
'war'+'rant'='WARRANT'
Can you help me to learn more?
(Other definitions for warrant that I've seen before include "Call for" , "Permit for arrest, search of premises, etc" , "Authorise, justify" , "Travel pass" , "Writ for arrest" .)