Such oral abuse makes a mortifying rebuff (1,4,2,3,5)
I believe the answer is:
a kick in the teeth
'such oral abuse' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'a mortifying rebuff' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
The remaining letters 'kickintheteeth' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'makes' is the link.
Can you help me to learn more?
(Other definitions for a kick in the teeth that I've seen before include "may knock the smile off one's face!" , "Such a hurtful rebuff" .)