Lewis & Short

pīpŭlum, i, n., and pīpŭlus, i, m. [pipo], a peeping, piping, chirping; hence,

  1. I. A whimpering, crying: filioli, Front. Ep. ad Anton. 1, 3 Mai.
  2. II. An outcry, upbraiding: te pipulo hic differam ante aedes, Plaut. Aul. 3, 2, 32; cf.: pipulo te differam id est convicio, declinatum a pipatu pullorum, Varr. L. L. 7, § 103 Müll.: pipulo poscere, Cn. Matius ap. Gell. 20, 9, 4.