Agitated, note, very agitated (5)
I believe the answer is:
nervy
'agitated' is the definition.
(thesaurus)
'note very agitated' is the wordplay.
'note' becomes 'n' (abbreviation).
'agitated' indicates an anagram.
'very' with letters rearranged gives 'ervy'.
'n'+'ervy'='NERVY'
(Other definitions for nervy that I've seen before include "On edge, tense" , "Anxious, jumpy" , "Highly-strung" , "Strained" , "Excitable" .)