yollotetl.

Headword: 
yollotetl.
Principal English Translation: 

literally, heart-stone; resolute, firm of heart; persevering, spirited, tough, stubborn (see Molina); hardened, constant, obstinate, tough, rebellious (see GDN)

IPAspelling: 
joːllohtetɬ
Alonso de Molina: 

yollotetl. constante y animoso, o duro y obstinado.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 40v. col. 2. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in Spanish: 

yollotetl = endurecido...constante...duro...obstinado...rebelde
Gran Diccionario Náhuatl, https://gdn.iib.unam.mx/termino/search?queryCreiterio=ocholli&queryParte...

themes: 
Behavior, Personality
See also: 
tetl.
yollotl.