To a soldier, denotes money of one’s own (7,5)
I believe the answer is:
private means
'money of one's own' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'to a soldier denotes' is the wordplay.
'to a soldier' becomes 'private' (private is a type of soldier).
'denotes' becomes 'means' (I've seen this in another clue).
'private'+'means'='PRIVATE MEANS'
Can you help me to learn more?
(Other definitions for private means that I've seen before include "Unearned income" , "make money from investments" , "source of income" , "Income other than salary" .)