Obnoxious friend interrupting over you once (6,3,4)
I believe the answer is:
beyond the pale
'obnoxious' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'friend interrupting over you once' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'interrupting' is an insertion indicator.
'over' becomes 'beyond' (I've seen this before).
'you once' becomes 'thee' (historical second person pronoun).
'beyond'+'thee'='beyondthee'
'pal' inserted within 'beyondthee' is 'BEYOND THE PALE'.
Can you help me to learn more?
(Other definitions for beyond the pale that I've seen before include "Intolerable, unacceptable" , "to be completely colourless?" , "Outside the bounds of acceptable behaviour" , "Morally or socially intolerable" , "Outside limits of social convention" .)