Some grim American seen as a religious leader (4)
I believe the answer is:
imam
'a religious leader' is the definition.
(I've seen this before)
'some grim american seen' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'IMAM' is hidden within 'grim american seen'.
'as' is the link.
(Other definitions for imam that I've seen before include "Muslim preacher" , "man of prayer" , "Muslim holy man" , "Mosque's prayer leader" , "Muslim prayer leader" .)