In the 1st century, the use of the Latin word plagiarius (literally kidnapper) to denote stealing someone else's work was pioneered by Roman poet Martial, who complained that another poet had "kidnapped his verses." "Plagiary", a derivative of "plagiarus" was introduced into English in 1601 by dramatist Ben Jonson to describe someone guilty of literary theft.
The derived form plagiarism was introduced into English around 1620. The Latin plagiārius, "kidnapper", and plagium, "kidnapping", has the root plaga ("snare", "net"), based on the Indo-European root *-plak, "to weave" (seen for instance in Greek plekein, Bulgarian "плета" pleta, Latin plectere, all meaning "to weave").
Plagiarism is the "wrongful appropriation" and "stealing and publication" of another author's "language, thoughts, ideas, or expressions" and the representation of them as one's own original work. The idea remains problematic with unclear definitions and unclear rules. The modern concept of plagiarism as immoral and originality as an ideal emerged in Europe only in the 18th century, particularly with the Romantic movement.
Plagiarism is considered academic dishonesty and a breach of journalistic ethics. It is subject to sanctions like penalties, suspension, and even expulsion. Recently, cases of 'extreme plagiarism' have been identified in academia.