Lewis & Short

sub-sĭlĭo, lŭi, 4, v. n. [salio], to spring upwards, leap up (mostly poet.; not in Cic.).

  1. I. Lit.: decido de lecto praeceps, subsilit, Plaut. Cas. 5, 2, 50; cf. id. Curc. 1, 2, 64: non subsilis ac plaudis? Varr. ap. Non. 135, 28: semper damnosi subsiluere canes, Prop. 4 (5), 8, 46: Pegasus adusque caelum subsilit ac resultat, App. M. 8, p. 208, 33: subsiliunt ignes ad tecta domorum, Lucr. 2, 191.
    1. * B. Trop.: subsiluisti et acrior constitisti, Sen. Ep. 13, 3.
  2. II. To leap into: jamdudum flammis dexteram objecimus aut voluntariam subsiluimus, Sen. Clem. 1, 3, 5.