Native American’s beliefs died out (4)
I believe the answer is:
cree
'native american's' is the definition.
(an indigenous people of North America)
'beliefs died out' is the wordplay.
'beliefs' becomes 'creed' (I've seen this before).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'out' suggests deleting specific letters.
'creed' with 'd' taken out is 'CREE'.
(Other definitions for cree that I've seen before include "tribesman" , "Native American tribe/language" , "American Indians" , "Member of an Algonquian people of central Canada" , "Alien language" .)