Principal English Translation:
something without a clear outcome or benefit, something in vain (see Karttunen)
Horacio Carochi / English:
nēmpancâ = particle, implying going ahead and doing something regardless of the results
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), 507.