ex-somnis (exomn-), e, adj. [somnus],
sleepless , wakeful , watchful (poet. and in post-Aug. prose; cf.: insomnis, vigil, vigilans): vir, Vell. 2, 88, 2: (Tisiphone) Vestibulum exsomnis servat noctesque diesque, Verg. A. 6, 556; Sil. 9, 5: animo exsomnis, Vell. 2, 127 fin.
exsomnis (exom-) e, adj.ex+somnus, sleepless, watchful : Vestibulum servat, V.: Euhias, H. ...
An Elementary Latin Dictionary