Marked by bucking or bucking up; (by extension) lively; brisk; jocund.
Spirited or lively, like a buck.
Capable of being shaped; malleable.
Easy to deal with or manage
Capable of being easily led, taught, or managed.
Sufficiently operationalizable or useful to allow a mathematical calculation to proceed toward a solution.
Algorithmically solvable fast enough to be practically relevant, typically in polynomial time.