Leader befitting in marked man? (7)
I believe the answer is:
captain
'leader' is the definition.
(I know that captain is a type of leader)
'befitting in marked man?' is the wordplay.
'befitting' becomes 'apt' (I've seen this in another clue).
'in' means one lot of letters goes inside another.
'marked man?' becomes 'cain' (as in the mark of Cain in the book of Genesis).
'apt' placed into 'cain' is 'CAPTAIN'.
(Other definitions for captain that I've seen before include "Leader" , "Skipper" , "Army rank" , "Is Pat Cain in charge of the ship?" , "Commander of a ship" .)