the foreskin of the penis (see Molina and Karttunen)
IPAspelling:
ʃipintɬi
Alonso de Molina:
xipintli. prepucio, capullo del miembro. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 159r. col. 2. Thanks to Joe Campbell for providing the transcription.
Frances Karttunen:
XIPIN-TLI prepuce, foreskin of the penis / prepucio, o capullo del miembro (M) This is only atttested in compounds and derived forms, all sharing the sense of ‘bump, protrusion.’ The attestations are divided between marking the vowels of the first and second syllables long or leaving them unmarked. The most common pattern is with a short vowel in the first syllable and a long vowel in the second. See XIPINTIC, XIPIPI. Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 326.