Lewis Short
(adjective) : trībŭlōsus, a, um, tribulus.
* Lit., full of thorns or thistles (late Lat.): voragines viarum,Sid. Ep. 3, 2 fin.
* Trop., thorny, rough: opus,Sid. Ep. 4, 3. —Sup.: tribulosissima dissimulatio,Sid. Ep. 1, 7 med.
Charlton T. Lewis, Charles Short, A Latin Dictionary