High priest having power over words (7)
I believe the answer is:
pontiff
'high priest' is the definition.
(I've seen this in another clue)
'power over words' is the wordplay.
I cannot really see how this works, but
'power' could be 'p' (symbol in physics) and 'p' is found within the answer.
'over' could be 'on' (physically on top of) and 'on' is found within the answer.
'words' could be 'tiff' (tiff is a kind of words) and 'tiff' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'having' acts as a link.
Can you help me to learn more?
(Other definitions for pontiff that I've seen before include "Religious leader" , "Head of the Roman Catholic church" , "Title for a pope" , "Bishop" , "High-priest" .)