Definition from Wiktionary, the free dictionary
- IPA: /ˈpleɪdʒəˌɹɪzm/
- (uncountable) The act of plagiarizing: the copying of another person's ideas, text, or other creative work, and presenting it as one's own, especially without permission.
- Though plagiarism in and of itself is not illegal, it is usually frowned upon; and many cases of plagiarism involve illegal copyright violation.
- (uncountable) Text or other work resulting from this act.
- The novel contained many instances of plagiarism; in fact, some entire passages were lifted verbatim from other novelists' work.
Related terms 
copying of someone's ideas
act of plagiarizing or something plagiarized