An incisive note? (5)

I believe the answer is:

sharp

I believe this is a double definition.

'an incisive' is the first definition.
(thesaurus)

'note?' is the second definition.
(thesaurus)

(Other definitions for sharp that I've seen before include "Keen-edged" , "Acidic; note" , "Acute; pointed" , "Note astute" , "exactly on time" .)

I've seen this clue in the Evening Standard.

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