This person's a married prayer leader (4)
I believe the answer is:
imam
'prayer leader' is the definition.
(I've seen this before)
'this person's a married' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
'married' could be 'm' (abbreviation, e.g. in genealogy) and 'm' is found within the answer.
'this person's' could be 'im' (('I am' - 'this person' means the crossword setter) and 'im' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for imam that I've seen before include "Ma, I'm off to find religious Muslim" , "Strict religious leader" , "Prayer leader in a mosque" , "Muslim preacher" , "Authority on Islamic doctrine and law" .)