For example unknown author is rejected when quite young (6)
I believe the answer is:
nonage
'quite young' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'for example unknown author is rejected' is the wordplay.
'for example' becomes 'e.g.' (short for 'exempli gratia', 'for example' in Latin).
'unknown author' becomes 'anon' (short for an anonymous author).
'is rejected' says the letters should be written in reverse.
'eg'+'anon'='eganon'
'eganon' in reverse letter order is 'NONAGE'.
'when' is the link.
Can you help me to learn more?
(Other definitions for nonage that I've seen before include "minority as before" , "In law, state of being under age for certain things" , "Period of immaturity" , "State of being unable to marry" , "Period of youth before maturity" .)