Lewis & Short

gannĭo, īre, v. n., to yelp, bark.

  1. I. Lit.: gannire cum sit proprie canum, Varro asinos rudere, canes gannire, pullos pipare dixit, Non. 450, 11: nictit canis in odorandis ferarum vestigiis leviter ganniens, Paul. ex Fest. s. v. nictit, p. 177 Müll.; cf. also ‡ gannitio.
    Of foxes, Auct. Carm. Phil. 59; Hier. Vit. Hilar. med.
  2. II. Transf., of persons.
    1. A. To snarl, growl, grumble (poet.): gannit odiosus omni totae familiae, Plaut. Fragm. ap. Varr. L. L. 7, § 103 Müll.: quid ille gannit? quid vult? Ter. Ad. 4, 2, 17; Cat. 83, 4; Afran. ap. Non. 450, 11; Juv. 6, 64.
    2. B. In gen., to talk loud, to gabble, chatter: sic nobis gannientibus, App. M. 3, p. 138.