- requiring much work, exertion, or perseverance: a laborious undertaking.
- characterized by or requiring extreme care and much attention to detail: laborious research.
- characterized by or exhibiting excessive effort, dullness, and lack of spontaneity; labored: a strained, laborious plot.
- given to or diligent in work: a careful, laborious craftsman.
- involving great exertion or long effort
- given to working hard
- (of literary style, etc) not fluent
adv.early 15c., “with difficulty, laboriously, slowly,” from laborious + -ly (2). Meaning “earnestly, strongly” is from c.1500. adj.late 14c., “hard-working, industrious,” from Old French laborios “arduous, wearisome; hard-working” (12c., Modern French laborieux), from Latin laboriosus “toilsome, wearisome, troublesome,” from labor (see labor (n.)). Meaning “costing much labor, burdensome” is from early 15c.; meaning “resulting from hard work” is mid-15c. Related: Laboriousness.