Lewis & Short

per-frīgesco, frixi, 3, v. inch. n.

  1. I. Lit., to grow very cold, to catch cold: ne canes perfrigescant, Varr. R. R. 2, 9, 13; Plin. 31, 6, 33, § 66: ei, qui perfrixit, opus est in laconico sedere, donec insudet, Cels. 1, 3: si perfrixit, cantat bene, Juv. 7, 194.
  2. II. Trop. (post-class.), M. Aur. ap. Front. Ep. ad M. Caes. 4, 5.