Jantirar is a title. It is borne historically by the head of the family holding the mountain fortress of Amba Sel in Ethiopia, similar to Wagshum, the heridary ruler of the province of Wag, and unlike other aristocratic titles like Meridazmach or Ras. While that artistocratic family is said to be one of the most noble in Ethiopian history, they never ruled any larger realm than their own district. Empress Menen Asfaw, consort of emperor Haile Selassie, was a daughter of Jantirar Asfaw of Ambassel.
The meaning of the title Jantirar makes it unique. The element Jan is the same as the Jan in Janhoye, another word used to refer to the Emperor of Ethiopia. Also, both words after Jan have almost similar meaning in Amharic. Hoye or hoyi can be roughly translated into "hear me, hear my call", while tirar is a form of Tira which means call or calling.
However, the claim that 'they never ruled any larger realm than their own district' can be challenged in many fronts. For example, while the mother of Yekuno Amlak was from Sagarat in the Dessie Zuria woreda, his father came from the highlands of Amba Sel. All the local folk histories and some remnants of the Axumite Kingdom, even before the Zagwe dynasty appears in history, around Lake Hayq of Amba Sel with a church that was founded in the 8th century, suggests that Ambassel and its immediate surrounding Amhara regions were well prepared to produce a king and a legend as it suits its kingdom. It is arguable that their Jantirar can not be so without some connection of their being the origin of Yekuno Amlak.