Etymology

prodigal

c.1450, back-formation from prodigiality (1340), from O.Fr. prodigalite (13c.), from L.L. prodigalitatem (nom. prodigalitas) "wastefulness," from L. prodigus "wasteful," from prodigere "drive away, waste," from pro- "forth" + agere "to drive" (see act). First ref. is to prodigial son, from Vulgate L. filius prodigus (Luke xv.11-32).