the world > relative properties > quantity > sufficient quantity, amount, or degree > abundance > [noun] > plenty or more than one reckons on (2)
Hence colloquial: Great, big. (Cf. thumping, adj. 2, bouncing, adj., etc.) Formerly often in phr. (now dialect) lumping pennyworth = ‘plenty for…
the full measure of something and then some; literal a measure of butter in which the quantities used exceed customary units.