Tolerant attitude initially overlooked in books on the French (7)
I believe the answer is:
lenient
'tolerant' is the definition.
(synonyms)
'attitude initially overlooked in books on the french' is the wordplay.
'attitude' becomes 'mien' (I've seen this before).
'initially overlooked' means to remove the first letter.
'in' is an insertion indicator.
'books on the french' becomes 'lent' (I can't explain this - if you can you should believe this answer much more).
'mien' with its first letter taken off is 'ien'.
'ien' placed within 'lent' is 'LENIENT'.
Can you help me to learn more?
(Other definitions for lenient that I've seen before include "Merciful or easygoing" , "Forgiving, gentle" , "Light" , "Indulgent, lax" , "Compassionate" .)