to be bald, or to have a receding hairline that goes to the top of one's head (see Molina)
Orthographic Variants:
quaxuxumulacqui, quaxoxomulacqui, quaxoxomolacqui
Alonso de Molina:
quaxuxumulacqui. ni. ser caluo, o tener entradas en la frente hasta lo alto de la cabeza. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 88r. col. 2. Thanks to Joe Campbell for providing the transcription.