Time of self-denial will have an effect finally (4)

I believe the answer is:

lent

'time of self-denial' is the definition.
(people deny themselves certain things during Lent)

'will have an effect finally' is the wordplay.
'finally' indicates one should take the final letters.
The final letters of 'will have an effect' are 'LENT'.

(Other definitions for lent that I've seen before include "Christian penitential season" , "Period from Ash Wednesday to Easter" , "Christian penitential period" , "Gave for a limited period" , "Time of fasting" .)

I've seen this clue in The Times.

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