Scared leaders of army facing attack (6)
I believe the answer is:
afraid
'scared' is the definition.
(similar in meaning)
'leaders of army facing attack' is the wordplay.
'leaders of' indicates taking the first letters.
'attack' becomes 'raid' (raiding is a kind of attacking).
The first letters of 'army facing' is 'af'.
'af'+'raid'='AFRAID'
(Other definitions for afraid that I've seen before include "Scared - politely regretful" , "wind up" , "Alarmed, fearful" , "Timorous" , "Scared, apprehensive" .)