The title of the king of the Mamprusi. The Encyclopedia of World Cultures entry on the Mamprusi gives nayiiri, glossing na as 'king, chief' and yiiri as 'house', and notes that unlike the Dagomba and Mossi royal titles it is not tied to the name of a territory. The king's village is Nalerigu. The same source says Mamprusi regard Dagomba kings as their 'junior brothers'.
The Nayiri is the king of the Mamprusi, whose seat is at Nalerigu.