atlacatl.

Headword: 
atlacatl.
Principal English Translation: 

a sailor; a bad person (see Molina and attestations)

Orthographic Variants: 
ahtlaca-tl
IPAspelling: 
ɑhtɬɑːkɑːtɬ
Alonso de Molina: 

atlacatl. marinero, o mal hombre.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 8r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

ĀTLAHCA–TL. M combines the definition of this and of AHTLĀCA–TL 'inhuman person' in a single entry. They both contrast with C's ĀTLĀCA–TL 'person made of water'. R does not indicate the internal glottal stop.

Lockhart’s Nahuatl as Written: 

natlacatl = I am a bad person, I am inhumane
This is an example of the way i gives way before any following vowel (in this case, a, the first letter of atlacatl). If it didn't give way, the word would be niatlacatl.
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 2.

Attestations from sources in English: 

The Matrícula de Huexotzinco includes a person named Felipe Amin who has an occupation listed as Tlatlama Atlacatl, which suggests that he is fishes perhaps from a boat. Thus, this atlacatl would be more akin to the translation as "sailor." (See f. 576r.)
Notes from Stephanie Wood. See the forthcoming entry in her Visual Lexicon of Aztec Hieroglyphs.)

a bad or inhuman person, monster. ah negative, tlacatl.
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 211.