noun, noun or participle which takes 'suru'
Refers to the act of working hard, often physically or mentally demanding effort. Can be used as a noun or with する to mean 'to labor'.
彼は長年の労作の末、ついに目標を達成した。
After years of toil, he finally achieved his goal.
この計画は大変な労作を要する。
This project requires considerable labor.
noun
painstaking work; work of great effort
Refers to the product or result of hard work, such as a book, research, or artwork that clearly involved great effort. Often used to praise someone's output.
この論文は彼の労作だ。
This paper is his painstaking work.
その辞書は数十年にわたる労作の結晶である。
That dictionary is the fruit of decades of painstaking effort.