tlacuahuac.

Headword: 
tlacuahuac.
Principal English Translation: 

something hard and heavy (see Molina)

Orthographic Variants: 
tlaquauac, tlaquahuac
Alonso de Molina: 

tlaquauac. cosa dura o empedernida.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 133v. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

tlaquauac (adjective) = strong, hard
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1877), 165.