Lewis & Short

Dēmosthĕnes, is

    (
  1. I. gen. i, Cic. Opt. Gen. 5, 14), m., Δημοσθένης, the most celebrated of the Grecian orators, Cic. de Or. 1, 13; 20; id. Brut. 9; Prop. 3 (4), 21, 27; Quint. 10, 1, 76; 12, 10, 23 sq.; Juv. 10, 114 et saep.
    Hence,
  2. II. Dēmosthĕnĭcus, a, um, adj., Demosthenic: Demosthenicum, quod ter primum ille vocavit (i. e. action), Aus. Prof. 1, 19.