Lewis & Short

implūmis (inpl-), e, adj. [2. in-pluma], without feathers, unfledged, callow.

  1. I. Lit. (poet. and in post-Aug. prose): assidens implumibus pullis avis, Hor. Epod. 1, 19: fetus columbarum, Plin. 11, 37, 64, § 170: coni (galearum), Sil. 8, 421; Ov. M. 6, 716.
  2. * II. Transf., without hair, bald: aliud in utero pilis vestitum, aliud inplume, Plin. 8, 55, 81, § 219.