TLACUĀHUA to harden /endurecerse o empedernirse algo (M). Z has the variant TLACUĀHUAYA. The long vowel of the second syllable is attested in B, C and Z, which is evidence against derivational relationship to CUAUHTI ‘to stiffen’ despite the affinity of meaning. M also has this as a transitive verb ‘to harden something.’ The intransitive and transitive verbs contrast in the preterit with TLACUĀHUAC and TLACUĀUH respectively.
TLACUĀHU(A) vt to harden something / endurecer algo (M). See TLACUĀHUA. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 257.