What is the Latin word for thorny?

The usual Latin words for “thorny” are spīnōsus, labōriōsus, arduus; also aerumnōsus. The right choice depends on the sense; see the distinctions below.

English → Latin

“thorny” in Latin

spīnōsusthorny, prickly labōriōsuslaborious, toilsome, demanding; industrious, hard-working arduuslofty, high, steep, tall, elevated; hard to reach, difficult, laborious, arduous aerumnōsussuffering, wretched, miserable

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

thorny

spinosus (only PROP.): laboriosus: arduus: aerumnosus (figuratively, troublesome). ☞ Disserendi spinae and spinosum disserendi genus signify “a subtle investigation,” not a “thorny” one (Vid: Cic., Fin., 3, 1, 3; 4, 28, 79).

Quick answer

What is the Latin word for thorny?: The usual Latin words for “thorny” are spīnōsus, labōriōsus, arduus; also aerumnōsus. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.