tecpin.

Headword: 
tecpin.
Principal English Translation: 

a flea (see Molina)

IPAspelling: 
tekpin
Alonso de Molina: 

tecpin. pulga.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 93v. col. 1. Thanks to Joe Campbell for providing the transcription.

Attestations from sources in English: 

Launey suggests that this is an example of a suffixless noun (no -tl, -tli, or -in ending). [But see the IDIEZ noun tecpimitl, with the -tl suffix, below.]
Michel Launey, An Introduction to Classical Nahuatl, translated and adapted by Christopher MacKay (Cambridge: Cambridge University Press, 2011), 232.

IDIEZ morfema: 
tecpin.
IDIEZ traduc. inglés: 
flea.
IDIEZ def. náhuatl: 
Nouhquiya TECPIMITL. Ce piltecuanitzin tlen nelcuecuetzin huan iixnezca cafentic zo yayahuic; motemah zo itztoqueh campa oncah tlalcuechtli zo campa pitzomeh cochih. “Tecpin tlan calaquiz pan ce acahya icxi pehua ahhuayohua. ”
IDIEZ gramática: 
tlat.
themes: 
Animals, Bugs, Insects, Reptiles, Fish, etc.