Lewis & Short

1. mūgĭo, īvi and ĭi, ītum, 4, v. n. [Sanscr. root, muǵ, sonare; Gr. μυκάομαι, μύζω], to low, bellow (syn. boo).

  1. I. Lit.: inde cum actae boves mugissent, Liv. 1, 7.
    Prov.: hic bove percusso mugire Agamemnona credit, Juv. 14, 286.
    Part. pres. subst.: mugientium Prospectat errantes greges, i. e. cattle, Hor. Epod. 2, 11.
  2. II. Transf., of the sound of a trumpet, to bray: Tyrrhenusque tubae mugire per aethera clangor, Verg. A. 8, 526.
    Of an earthquake, to rumble: sub pedibus mugire solum, id. ib. 6, 256.
    Of a mast: si mugiat Africis Malus procellis. groans, Hor. C. 3, 29, 57.
    Of thunder, to roar, crash, peal: mugire tonitrua, rutilare fulgura, Min. Fel. Octav. 5: quasi mugiente litterā M. Quint. 12, 10, 31: at tibi tergeminum mugiet ille sophos, will bellow or cry out to you, σοφῶς, well done! bravo! Mart. 3, 46, 8.
    Also, to reject with a sound: cruentum mugiit, spat gore, Claud. Ruf. 1, 66.