Moralising nun sees to it unhappily (11)

I believe the answer is:

sententious

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'moralising nun sees to it unhappily' is the definition.
I can't tell whether this defines the answer.

'nun sees to it unhappily' is the wordplay.
'unhappily' is an anagram indicator.
'nun'+'sees'+'to'+'it'='nunseestoit'
'nunseestoit' with letters rearranged gives 'SENTENTIOUS'.

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(Other definitions for sententious that I've seen before include "Given to pompous moralising" , "Pompously moralistic" , "Pompously moralising" .)

I've seen this clue in The Times.

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