Definition & Meaning of "piece of work"in English

What is the origin of the idiom "piece of work" and when to use it?

"Piece of work" is a slang expression that appeared in English in the early 20th century, originally meaning a thing created or done, later applied to people to describe someone difficult, unpleasant, or extraordinary in behavior. The phrase emphasizes notable or challenging traits, sometimes with admiration but often with criticism. It is used in informal, conversational contexts, including speech, media, and writing, to comment on someone's personality or actions. The term is context-dependent: it can be mildly critical, strongly negative, or even admiring, depending on tone.