an unpleasant (acidic) smell, such as a belch or the like (see Molina)
IPAspelling:
ʃokohjɑːk
Alonso de Molina:
xocoyac. azedo olor, assi como regueldo o cosa semejante. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 160v. col. 1. Thanks to Joe Campbell for providing the transcription.