Liberal invited occasionally during religious season (7)
I believe the answer is:
lenient
'liberal' is the definition.
(thesaurus)
'invited occasionally during religious season' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'during' means one lot of letters goes inside another.
'religious season' becomes 'Lent' (period of fasting before Easter).
The alternating letters of 'invited' are 'nie'.
'nie' put into 'lent' is 'LENIENT'.
(Other definitions for lenient that I've seen before include "Forbearing" , "Soft-hearted" , "Showing tolerance" , "Merciful or easygoing" , "Compassionate" .)