Lewis Short
(verb) : dē-rŭo, rŭi, 3, and n. (a very rare word).
* Act., to throw or cast down.
* Lit.: hiems immensam vim aquarum ruptis nubibus deruat,Sen. Q. N. 3, 27.
* Neutr., to fall down: Ap. M. 2, p. 128; 7, p. 196.
Charlton T. Lewis, Charles Short, A Latin Dictionary