chieftain vs tribal chief

chieftain and tribal chief both are nouns.

Word	Noun	Adjective	Verb	Adverb
chieftain	Yes	No	No	No
tribal chief	Yes	No	No	No

As nouns, chieftain and tribal chief are synonyms defined as:

Other synonyms of chieftain include chief, headman.

chieftain (noun)	tribal chief (noun)
the head of a tribe or clan	the head of a tribe or clan
the leader of a group of people