Marked by or requiring long, hard work: spent many laborious hours on the project. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "laborious" in a sentence
"The unfortunate reputation that writing often bears as being boring and laborious is likely a result of people writing about uninteresting topics and doing so only out of necessity."
"For the most part it was a silent forest, lush and dank, where only occasionally a wood-pigeon cooed or snow - white cockatoos laughed harshly in laborious flight."
"If woman be the weaker creature, why is she employed in laborious avocations? why compelled to endure the fatigue of household drudgery; to scrub, to scower, to labour, both late and early, while the powdered lacquey only waits at the chair, or behind the carriage of his employer?"