Principal English Translation: 

to fit well

Frances Karttunen: 

-PANI irregular verb; pret: -PANIC to go well with / convenir, ir bien (S) [(3)Cf.123r]. This item takes possessive rather than subject prefixes and is always sg. in form.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 186.

Horacio Carochi / English: 

-pani = to fit well
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 509, and see 452–53 (with n2)