a piece of fruit that is not ripe, hard, green, without flavor
Alonso de Molina:
xoxoctetl. fruta verde, dura y sin sazon Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 161v. col. 1. Thanks to Joe Campbell for providing the transcription.