Lewis & Short

sŭperventus, ūs, m. [supervenio], a coming up or upon, an arrival (post-Aug.).

  1. I. In gen., Plin. 7, 15, 13, § 64; Tac. H. 2, 54.
  2. II. In partic., in milit. lang., an attack, Veg. Mil. 3, 8; 3, 22.