Showing some armour, is aware of armistice, we hear (9)
I believe the answer is:
nosepiece
'showing some armour is' is the definition.
I can't judge whether this definition defines the answer.
'aware of armistice we hear' is the wordplay.
'aware of' becomes 'nose' (I can't explain this - if you can you should give a lot more credence to this answer).
'armistice' becomes 'peace' (I've seen this in another clue).
'we hear' indicates a 'sounds like' (homophone) clue.
'peace' is a homophone of 'piece'.
'nose'+'piece'='NOSEPIECE'
Can you help me to learn more?
(Other definitions for nosepiece that I've seen before include "Protector" , "Nozzle" , "Guard at front" , "Part of a helmet protecting the schnozzle" , "bit of protection" .)