Note I'm unusually punctual (2,4)
I believe the answer is:
on time
'punctual' is the definition.
(similar in meaning)
'note i'm unusually' is the wordplay.
'unusually' is an anagram indicator.
'note'+'im'='noteim'
'noteim' anagrammed gives 'ON TIME'.
(Other definitions for on time that I've seen before include "promptly" , "(Of train) not late" , "Arriving when due" , "Punctual, not late" , "Not running late" .)