Set of beliefs Indian abandoned finally (5)
I believe the answer is:
creed
'set of beliefs' is the definition.
(I've seen this before)
'indian abandoned finally' is the wordplay.
'indian' becomes 'cree' (Cree is an example).
'finally' says to take the final letters.
The final letter of 'abandoned' is 'd'.
'cree'+'d'='CREED'
(Other definitions for creed that I've seen before include "System of religious belief" , "System of belief, faith" , "Summary of articles of religious belief" , "Catechism" , "Religious doctrine" .)