"expressing or characterized by sadness or mournfulness; doleful," c. 1600, formerly also lugubrous, from -ous + Latin lugubris "mournful, doleful, pertaining to mourning," from lugere "to mourn," from PIE root *leug- "to break; to cause pain" (source also of Greek lygros "mournful, sad," Sanskrit rujati "breaks, torments," Lettish lauzit "to break the heart"). Related: Lugubriously; lugubriousness.