I recall religious celebration certainly justified, originally (9)
I believe the answer is:
jerusalem
'i' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'recall religious celebration certainly justified originally' is the wordplay.
'recall' says the letters should be written in reverse.
'religious celebration' becomes 'mela' (fair or hindu festival).
'certainly' becomes 'sure' (synonyms).
'originally' says to take the initial letters.
The initial letter of 'justified' is 'j'.
'mela'+'sure'+'j'='melasurej'
'melasurej' backwards is 'JERUSALEM'.
Can you help me to learn more?
(Other definitions for jerusalem that I've seen before include "disputed city" , "Holy city of Muslims, Jews and Christians" , "Knobbly edible tuber" , "Israeli capital" , "See 17" .)