Native American doctrine unfinished (4)
I believe the answer is:
cree
'native american' is the definition.
(an indigenous people of North America)
'doctrine unfinished' is the wordplay.
'doctrine' becomes 'creed' (creed is a kind of doctrine).
'unfinished' means to remove the last letter.
'creed' with its last letter taken away is 'CREE'.
(Other definitions for cree that I've seen before include "Soften up" , "American Indians" , "Native American; rhymes with French cheese" , "North American Indian" , "Native American people" .)