Something that requires a lot of hard work
Laborious describes something that requires a lot of hard work, such as Victor Frankenstein’s laborious undertaking of digging graves to find monster parts.
Laborious comes from the familiar word for work, labor, which doesn’t veer far from its roots in Old French meaning “exertion of the body,” and from Latin “toil, pain, exertion, fatigue.” Anything that requires blood, sweat, and tears is laborious, and while it’s usually a good thing to work hard, laborious can also describe something over-thought, such as the heavy-handed plot of a bad TV show. Think labor plus boring, said like an old-fashioned English aristocrat: luh-bohr-ee-uhs.
Thanks to Vocabulary.com