Third son (4)
I believe the answer is:
seth
'third son' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for seth that I've seen before include "Indian novelist, Vikram" , "Adam and Eve's third son" , "Early man" , "In disguise, the brother of Cain and Abel" , "Vikram --, Indian author" .)