First to go, he left after Abraham (4)
I believe the answer is:
abel
'first to go he' is the definition.
The definition suggests a singular noun which matches the answer.
'left after abraham' is the wordplay.
'left' becomes 'l' (common abbreviation).
'after' says to put letters next to each other.
'abraham' becomes 'abe'.
'l' put after 'abe' is 'ABEL'.
Can you help me to learn more?
(Other definitions for abel that I've seen before include "murdered second son?" , "done in before anyone else" , "Brother killed by Cain" , "character in the Bible" , "Biblical murder victim" .)