The last word from leader of Assamese soldiers, ... (4)
I believe the answer is:
amen
'the last word' is the definition.
(I've seen this before)
'leader of assamese soldiers' is the wordplay.
'leader of' says to take the initial letters.
'soldiers' becomes 'men' (I've seen this before**).
The initial letter of 'assamese' is 'a'.
'a'+'men'='AMEN'
'from' acts as a link.
(Other definitions for amen that I've seen before include "Final word in prayer" , "Prayerful last word" , "Last word of prayer" , "Religiously 11 [THE LASTWORD]" , "Conclusion of prayer" .)