Literary work — another best seller gets permit (6,7)
I believe the answer is:
belles lettres
'literary work' is the definition.
(belles lettres is a kind of literary work)
'another best seller gets permit' is the wordplay.
I cannot really see how this works, but
'another' could be 're' (I've seen this in other clues) and 're' is present in the answer.
'permit' could be 'let' (synonyms) and 'let' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for belles lettres that I've seen before include "Literary works" , "writings" , "literary studies" .)