Note awfully mean invasive procedure (5)
I believe the answer is:
enema
'invasive procedure' is the definition.
'enema' can be an answer for 'procedure' (I have seen 'medical procedure' mean 'enema' so perhaps 'procedure' could also mean 'enema'). I'm not sure about the 'invasive' bit.
'note awfully mean' is the wordplay.
'note' becomes 'e' (musical note).
'awfully' indicates an anagram.
'mean' is an anagram of 'nema'.
'e'+'nema'='ENEMA'
Can you help me to learn more?
(Other definitions for enema that I've seen before include "The bottom line in medical treatment?" , "process to ensure evacuation" , "Medical liquid introduced anally" , "fundamental procedure?" , "Rectal medicine" .)