Prayer word (4)
I believe the answer is:
amen
'prayer word' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for amen that I've seen before include "Word of approval" , "Conclusion of prayer" , "Churchgoer's assent?" , "Prayerful last word" , "Word at the end of a prayer" .)