Message of importance (4)

I believe the answer is:

note

I believe this is a double definition.

'message' is the first definition.
(note is a kind of message)

'importance' is the second definition.
(thesaurus)

'of' is the link.

(Other definitions for note that I've seen before include "Heed; short letter" , "Bill" , "Observe; short letter" , "Eg, fiver; annotation" , "A flat, for example" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app