Human being (6)
'human being' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for person that I've seen before include "anyone else" , "he's the third" , "Individual human being" , "character" , "present appearing in this" .)
(Other definitions for mortal that I've seen before include "Subject to death, like all mankind" , "Human - transitory" , "Sound a wound is deadly" , "Destined to die" , "Human being, subject to death" .)