Keeping quiet, with some little doubt (12)

I believe the answer is:

preservation

'keeping' is the definition.
(I've seen this before)

'quiet with some little doubt' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'with' says to put letters next to each other.
'some little doubt' becomes 'reservation'.
'p'+'reservation'='PRESERVATION'

(Another definition for preservation that I've seen is " Keeping".)

I've seen this clue in The Guardian.

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