What is the difference between anger and frustration? Many times in the suttas the monks are said to be frustrated, but the word anger is never used.. what is the difference?

My short thought is - anger is seeing wrong speech or action, and saying 'why are you acting this way - it hurts the other', whilst frustration is 'why are you acting this way - it hurts you'.

Any thoughts on this from respectable sources?
If I remember correctly my Abhidharma lectures, both anger and frustration are the types of aversion. Anger is how aversion manifests when you feel that you are stronger than the object of your aversion, while frustration is when you feel weaker than the object/cause of aversion.