xolopitli.

Headword: 
xolopitli.
Principal English Translation: 

idiot, simpleton, fool, dolt (see Molina, Lockhart, and Karttunen); also attested in contemporary Nahuatl as the devil (see attestations)

Orthographic Variants: 
xolopictli
IPAspelling: 
ʃolopihtɬi
Alonso de Molina: 

xolopitli. bouo, o tonto.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 161r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

XOLOPIH-TLI pl: -TIN idiot, fool, dolt / bobo o tonto (M).
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 330.

Lockhart’s Nahuatl as Written: 

idiot, simpleton
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 241.

Attestations from sources in English: 

in xolopitin huehuentoton = the fools and little old men
Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 85.

In xolopitli tlacateccatl tlacochcalcatl, tlaouitilia, tlamictia, atoiatl tepexitl quiteittitia. = The stupid commanding general, [or] general, causes trouble, causes death, leads one into danger. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 10 -- The People, No. 14, Part 11, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 24.

injc amo tixolopitli, tixtotomac, timjllacatl, titequjmjllacatl ipan timachoz = Also thou art not to cry out, lest thou be known as an imbecile, a shameless one, a rustic, very much a rustic (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 122.

Attestations from sources in Spanish: 

in xolopitin huehuentoton = los viejos de la siega gentilidad Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 84–85.

intlacamo oquitetlaneuhtini, camo onicquixtilisquia. Onicquixtili ypanpa huel xolopitin in oquintlaneuhti = Si no lo hubiese arrendado, no se lo habría tomado yo. Yo se lo tomé porque fueron unos idiotas a quienes se lo arrendó. (Amecameca, 1746)
Frances Karttunen and James Lockhart, "Textos en náhuatl del siglo XVIII: Un documento de Amecameca, 1746," Estudios de Cultura Náhuatl 13 (1978), 153–175, ver 155.

In xolopitli ihuan tlacatl = El demonio y el hombre (s. XX, Milpa Alta)
Los cuentos en náhuatl de Doña Luz Jiménez, recop. Fernando Horcasitas y Sarah O. de Ford (México: UNAM, 1979), 46–47.

Mitoa que mach ompoyon omochantitaya inon amocuali, quicuitia xolopictli nozo demonio. = Cuentan que allí habitaba aquel malvado que llaman el pingo o demonio. (s. XX, Milpa Alta)
Los cuentos en náhuatl de Doña Luz Jiménez, recop. Fernando Horcasitas y Sarah O. de Ford (México: UNAM, 1979), 94–95.

Oquitoc inin xolopitli. = Contestó el pingo. (s. XX, Milpa Alta)
Los cuentos en náhuatl de Doña Luz Jiménez, recop. Fernando Horcasitas y Sarah O. de Ford (México: UNAM, 1979), 96–97.