One is a leader of Muslims (4)
I believe the answer is:
imam
This could be a double definition.
'one is a leader' is the first definition.
(I know that imam is a type of leader)
'of muslims' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for imam that I've seen before include "Islamic prayer leader" , "man of prayer" , "Muslim community leader" , "Muslim holy man" , "Islamic religious leader" .)