something that makes things dirty (a metaphor) (see Molina)
Alonso de Molina:
teizolo. cosa que ensuzia. metaphora. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 94v. col. 1. Thanks to Joe Campbell for providing the transcription.