Alienate European doctor with extraordinary powers (8)
I believe the answer is:
estrange
'alienate' is the definition.
(synonyms)
'european doctor with extraordinary powers' is the wordplay.
I cannot quite see how this works, but
'european' could be 'e' (abbreviation e.g. EU) and 'e' is located in the answer.
'extraordinary' could be 'strange' (similar in meaning) and 'strange' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for estrange that I've seen before include "As Regent (anag.)" , "disunity" , "Get cut off" , "Reagents (anag.)" , "may break up" .)