runny-nosed, or full of mucus; or, possibly, a brat (see Molina)
Alonso de Molina:
yacatzotecuicuitlapul. mocoso. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 30v. col. 1. Thanks to Joe Campbell for providing the transcription.