I'm sorry name-drop is inappropriate (6,2)
I believe the answer is:
pardon me
'i'm sorry' is the definition.
'name-drop is inappropriate' is the wordplay.
'is inappropriate' indicates anagramming the letters (an improper or inaccurate order for the letters).
'name'+'drop'='namedrop'
'namedrop' with letters rearranged gives 'PARDON ME'.
(Other definitions for pardon me that I've seen before include "Polite apology" , "Sorry" , "Say that again!" .)