From Middle English cheveteyn, cheftayne, from Old French chevetaine, from Late Latin capitaneus (English captain), from Latin caput (“head”), from Proto-Indo-European *kauput- (English head), itself from Proto-Indo-European *kap-. Doublet of captain; related to chief.

• IPA^(key): /ˈt͡ʃiːf.tən/, /ˈt͡ʃiːf.tɪn/

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chieftain (plural chieftains)

1. A leader of a clan or tribe.
   • 1907, Yosaburo Takekoshi, “THE SAVAGES AND THEIR TERRITORY.”, in George Braithwaite, transl., Japanese Rule in Formosa‎^[1], Longmans, Green, and Co., →OCLC, page 225:

     VI. THE PUYUMA GROUP.
     The tribes belonging to this group occupy the plains in Hinan and that neighbourhood, and call themselves "Puyumas," but the Chinese call them the "Hinan Savages". The Puyumas formed a very powerful State some 300 years ago, and united under one single rule as many as seventy isolated tribes scattered over the land, stretching from Hakusekikwaku and Seikoko to Harogwai in the southern part of the island, and were at one time so powerful that the chieftain was called by foreigners "The King of Hinan".

   • 1970, Kazimierz Godłowski, “The chronology of the Late Roman and early migration periods in Central Europe”, in Acta scientiarum litterarumque: Schedae archeologicae‎^[2], Nakładem Uniwersytetu Jagiellonśkiego, page 22:

     They were probably the work of individual craftsmen working to meet the chieftains' needs. Their place in the chronology of the big cemeteries is indicated by the less richly-decorated double-springed bronze brooches which are found here.

2. (by extension) A leader of a group.

   The robber chieftain divided up the spoils.

• (leader of a clan or tribe): chief, big gun, big shot, big wheel, bigwig, boss, employer, foreman, head, leader, mandarin, manager, mover and shaker, top banana, top dog, tycoon

From Middle Scots chiftane, chyftane, from Early Scots chefftane, from Middle English cheftayne, from Old French chevetaine, from Late Latin capitaneus, from Latin caput (“head”), from Proto-Indo-European *kauput-.

• IPA^(key): [tʃiften]

chieftain (plural chieftains)

1. chieftain
2. (possibly) schore; leader of a Highlands clan

• “chieftain”, in The Dictionary of the Scots Language, Edinburgh: Scottish Language Dictionaries, 2004–present, →OCLC.