Rub American uncle up the wrong way with authority (7)
I believe the answer is:
massage
'rub' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for massage that I've seen before include "Relaxing manipulation" , "Manipulation of the muscles" , "Present favourably" , "Manipulate to get better results" , "Knead" .)