President — genuine fellow but spurned English (6)
I believe the answer is:
'president' is the definition.
(Harry S Truman)
'genuine fellow but spurned english' is the wordplay.
'genuine' becomes 'true' (synonyms).
'fellow' becomes 'man' (fellow can mean a man).
'but spurned' indicates named letters should be taken away.
'english' becomes 'e' (abbreviation).
'trueman' with 'e' taken out is 'TRUMAN'.
(Other definitions for truman that I've seen before include "Harry S ...... was USA president 1945-53" , "US president, 1945-53" , "- - Capote (lit.)" , "Harry S ... was 33rd US President" , "The - Show, Jim Carrey film" .)