also: りょくさく
noun
painstaking work; work of great effort; outstanding work
Only with reading りきさく
A work, piece, or production into which considerable effort has clearly been put; often complimentary, as in a major or ambitious work by an artist, writer, director, student, etc.
この小説は、十年をかけて書かれた力作だ。
This novel is a painstaking work written over ten years.
学生
There were many impressive works among the students' graduation projects.
noun, noun or participle which takes 'suru'
Only with reading りょくさく
Formal or literary use, especially with the reading りょくさく, meaning exerting effort or laboring hard. This is uncommon in modern everyday Japanese and should not be confused with the common りきさく sense.
古い文章では、「力作する」が「骨を折って働く」という意味で使われることがある。
In older writing, 力作する can be used to mean working hard or toiling.