Activity, energeia, is the coming-forth of that good condition from its state of concealment or mere potentiality; it is its flourishing or blooming. Without that the good condition is seriously incomplete.
Nussbaum defines energeia as the actualization of virtue from potentiality into manifest activity, arguing that without this coming-forth a good condition remains essentially deficient.
, The Fragility of Goodness: Luck and Ethics in Greek Tragedy and Philosophy, 1986thesis