Maybe turn out a master or president (6)
I believe the answer is:
truman
'president' is the definition.
(Harry S Truman)
'maybe turn out a master' is the wordplay.
'maybe' is an anagram indicator.
'out' means one lot of letters goes inside another.
'a master' becomes 'ma'.
'turn' is an anagram of 'trun'.
'trun' going around 'ma' is 'TRUMAN'.
'or' acts as a link.
(Other definitions for truman that I've seen before include "US president, 1945-53" , "The - Show, Jim Carrey film" , "Harry S . . . . . ., American president who ordered the dropping of the atom bomb" , "Harry S ..., former president of USA" , "American president who ordered use of atomic bomb" .)