Lewis Short
insĭdĭātor (noun M) : id.
* A soldier lying in ambush, Hirt. B. G. 8, 18.
* Transf., one who lies in wait, a lurker, waylayer (rare but class.): viae,Cic. Cat. 2, 12, 27: in foro collocatur,id. Mil. 7, 19: imperii,Nep. Reg. 2.
Charlton T. Lewis, Charles Short, A Latin Dictionary