Lewis & Short

immātūrĭtas (inm-), ātis, f. [immaturus].

  1. I. Unripeness, immatureness: sponsarum, Suet. Aug. 34.
  2. * II. Untimely haste, over-eagerness: quid haec festinatio, quid haec immaturitas tanta significat? Cic. Quint. 26, 82.