Bleep has been replaced with medium curse (9)
I believe the answer is:
blaspheme
'curse' is the definition.
(I know that curse can be written as blaspheme)
'bleep has been replaced with medium' is the wordplay.
'been replaced' indicates an anagram.
'with' is an insertion indicator.
'medium' becomes 'm' (as in UK clothing sizes).
'bleep'+'has'='bleephas'
'bleephas' with letters rearranged gives 'blasphee'.
'blasphee' going around 'm' is 'BLASPHEME'.
(Other definitions for blaspheme that I've seen before include "Speak profanely" , "Talk irreverently about God and sacred things" , "Utter obscenities or profanities" , "Say irreverent things about God" , "Speak irreverently about God" .)