Prepared to fight rather than leg it (5)
I believe the answer is:
'prepared' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for armed that I've seen before include "with Browning?" , "Bearing weapons" , "Being equipped with 25 Across" , "equipped for fighting" , "Gave weapon" .)