LABORIOUS Copy link • LABORIOUS Using labor, laboriosus (Cic., Nep.). Requiring labor, laboriosus, operosus, laboris plenus (full of labor): magni, or multi, operis (that calls for much labor): very laborious, immensi laboris, operis: a laborious work, opus operosum; opus et labor (concrete); labor operosus (abstract; exertion with labor).