Warrior prince on battleground injures soldier (5,7)
I believe the answer is:
field marshal
'warrior' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'prince on battleground injures soldier' is the wordplay.
'prince' becomes 'hal' (name for Prince Henry in Shakespeare's histories).
'on' means one lot of letters go next to another.
'battleground' becomes 'field' (synonyms).
'injures soldier' becomes 'mars' (I can't justify this - if you can you should give a lot more credence to this answer).
'field'+'mars'='fieldmars'
'hal' put after 'fieldmars' is 'FIELD-MARSHAL'.
Can you help me to learn more?
(Other definitions for field marshal that I've seen before include "general? He's more important than that" , "military leader" , "Highest rank in British army" , "Highest-ranking army officer" .)