Society described by letter (10)
I believe the answer is:
permissive
'society described' is the definition.
I can't judge whether this defines the answer.
'by letter' is the wordplay.
'by' becomes 'per' (I've seen this in another clue).
'letter' becomes 'missive' (synonyms).
'per'+'missive'='PERMISSIVE'
Can you help me to learn more?
(Other definitions for permissive that I've seen before include "Like our society" , "granting authorisation" , "Liberal, broad-minded" , "Free" , "Lenient, indulgent" .)