Make unholy din, mostly meaningless (9)

I believe the answer is:

dishallow

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'make unholy' is the definition.
I can't judge whether this definition defines the answer.

'din mostly meaningless' is the wordplay.
'mostly' means to remove the last letter (most but not all of the word).
'meaningless' becomes 'shallow' (I can't justify this - if you can you should believe this answer much more).
'din' with its last letter taken away is 'di'.
'di'+'shallow'='DISHALLOW'

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I've seen this clue in The Times.

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