Oppose a hundred in the battle-line (8)
I believe the answer is:
confront
'oppose' is the definition.
(I've seen this before)
'a hundred in the battle-line' is the wordplay.
'a hundred in' becomes 'con' (I can't justify this - if you can you should believe this answer much more).
'the battle line' becomes 'front' (I've seen this in another clue).
'con'+'front'='CONFRONT'
Can you help me to learn more?
(Other definitions for confront that I've seen before include "Face up to (a problem)" , "Challenge" , "Meet face to face with" , "Square up to" , "Oppose head-on" .)