Musical instrument's horrible groan (5)

I believe the answer is:

organ

'musical instrument's' is the definition.
(organ is a kind of musical instrument)

'horrible groan' is the wordplay.
'horrible' indicates anagramming the letters.
'groan' anagrammed gives 'ORGAN'.

(Other definitions for organ that I've seen before include "Pipe or reed instrument" , "May be in the loft" , "notes issue from this" , "periodical" , "Possibly the heart" .)

I've seen this clue in The Guardian.

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