Webster’s Revised Unabridged Dictionary · 1913
Laborious
La·bo′ri·ous, a. [L. laboriosus,fr. labor labor: cf. F. laborieux.] 1. Requiring labor, perseverance, or sacrifices; toilsome; tiresome.
Dost thou love watchings, abstinence, or toil, Laborious virtues all ? Learn these from Cato. Addison.
2. Devoted to labor; diligent; industrious; as, a laborious mechanic.
— La·bo′ri·ous·ly, adv. — La·bo′ri·ous·ness, n.