Goodwill from alternative military institution towards young leaders (5)
I believe the answer is:
amity
'goodwill' is the definition.
(I've seen this before)
'alternative military institution towards young leaders' is the wordplay.
'leaders' indicates taking the first letters.
The first letters of 'alternative military institution towards young' is 'AMITY'.
'from' acts as a link.
(Other definitions for amity that I've seen before include "warmth" , "Friendly feeling, fraternity" , "Accord" , "Friendly relations" , "Friendliness" .)