Meaning of wild oat

wild' oat'

Pronunciation: [key]
  1. any uncultivated species of Avena, esp. a common weedy grass, A. fatua, resembling the cultivated oat.
  2. a hardy plant, Uvularia sessilifolia, of the lily family, of eastern North America, having deep green, hairy leaves and greenish-yellow, tubular flowers.
  3. to have a youthful fling at reckless and indiscreet behavior, esp. to be promiscuous before marriage.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.