Lewis & Short

fūnārĭus, a, um, adj. [funis],

  1. I. of or belonging to a rope (post-class.): equus, i. q. funalis equus, an extra horse, trace-horse, Isid. Orig. 18, 35, 2.
  2. II. Subst.: Fūnā-rĭus, ii, m., a surname of Gratianus, father of the emperor Valentinianus (so called from his bodily strength, because five men could not drag a rope out of his hands), Aur. Vict. Epit. 45; Amm. 30, 7, 2.