Support military commander with inside information (10)
I believe the answer is:
propaganda
'information' is the definition.
(propaganda is a kind of information)
'support military commander with inside' is the wordplay.
'support military' becomes 'prop' (I can't explain this - if you can you should believe this answer much more).
'commander' becomes 'aga' (I've seen this before).
'with' becomes 'and' (I've seen this before).
'inside' indicates putting letters inside.
'aga' placed around 'and' is 'aganda'.
'prop'+'aganda'='PROPAGANDA'
Can you help me to learn more?
(Other definitions for propaganda that I've seen before include "'Spin'" , "messages" , "organised spread of information" , "Indoctrination" , "Dissemination of information" .)