Religious festival date: years off (6,3)
I believe the answer is:
easter day
'religious festival' is the definition.
'easter day' can be an answer for 'festival' (I have seen 'Christian festival ' mean 'easter day' so perhaps 'festival' could also mean 'easter day'). I'm unsure of the 'religious' bit.
'date years off' is the wordplay.
'off' indicates an anagram.
'date'+'years'='dateyears'
'dateyears' with letters rearranged gives 'EASTER DAY'.
Can you help me to learn more?
(Other definitions for easter day that I've seen before include "Time of Christian festival" , "Egg-giving time" , "eggs on this occasion" , "part of holiday?" , "When Christians celebrate the Resurrection" .)