momoyactli.

Headword: 
momoyactli.
Principal English Translation: 

a warrior outfit made primarily of red feathers; the accompanying headdress also had two rows of green and white feathers; or, that which is dispersed

Attestations from sources in English: 

momoyactli = "momoyactli is derived from the verb momoyahua, which means to flee, or disperse. Beyer translates momoyactli as "lo que se dispersa" (that which is scattered) , stating that the name refers to the fanning out of the feathers."
Frances Berdan and ‎Patricia Rieff Anawalt, The Essential Codex Mendoza (1997), Volume 2 or Volume 4, 202.

It may have been a feather crest on a wooden frame. The feathers of the momoyactli headdress are shorter and less compact, seemingly less prestigious than the pazactli.
Justyna Olko, Insignias of Rank in the Nahua World (2014), 128.

As a reward for five captives, one could obtain a reward of a "back ornament with a fan" of feathers in the form of a momoyactli (a type of tlahuiztli) of scarlet macaw feathers.
John Pohl, Aztec Warrior (2012), 22.