one who helps someone else and receives the same pay back (i.e. a person who loans another person money and gets paid back?) (see Molina)
Alonso de Molina:
tlamacoalli. ayudador del que despues le ha de ayudar, pagandole enla mesma moneda &c. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 125r. col. 2. Thanks to Joe Campbell for providing the transcription.