Lewis & Short

Harpŏcrătēs, is, m., = Ἁρποκράτης,

  1. I. The Egyptian god of silence, represented with his finger on his mouth; acc. to others, a Greek philosopher, who enjoined silence respecting the nature of the gods, Varr. L. L. 5, § 57 Müll. N. cr. (cf. Ov. M. 9, 692).
  2. * II. Transf., a silent person, Cat. 74, 4.