Well able to engage the enemy? (8,3)
I believe the answer is:
fighting fit
'well' is the definition.
I don't know anything about this answer so I can't tell whether this works.
'able to engage the enemy?' is the wordplay.
'able' becomes 'fit' (similar in meaning).
'to' says to put letters next to each other (I've seen this in other clues).
'engage the enemy?' becomes 'fighting' (I can't explain this - if you can you should give a lot more credence to this answer).
'fit' put after 'fighting' is 'FIGHTING FIT'.
Can you help me to learn more?
(Other definitions for fighting fit that I've seen before include "Standing up to attack of illness" , "in good shape" , "In great form" , "In good physical condition" , "very well" .)