Wikipedia:Close paraphrasing

Close paraphrasing, or patchwriting, is the superficial modification of material from another source. Editors should generally summarize source material in their own words, adding inline citations as required by the sourcing policy.

Limited close paraphrasing is appropriate within reason, as is quoting, so long as the material does not violate copyrights and is cited and (for biased statements of opinion) clearly attributed in the text – for example, by adding "John Smith wrote ...", together with a footnote containing the citation at the end of the clause, sentence or paragraph. Limited close paraphrasing is also appropriate if there are only a limited number of ways to say the same thing.

Close paraphrasing without in-text attribution may constitute plagiarism, and when extensive (with or without in-text attribution) may also violate Wikipedia's copyright policy, which forbids Wikipedia contributors from copying an excessive amount of material directly from other sources. Although in legal terms it's not possible to have close paraphrasing of a work without copyright protection, Wikipedia's own rules require public domain material to be cited. Public domain material may have in-text attribution where appropriate. If the source material bears a free copyright license that is compatible with Wikipedia's licenses, copying or closely paraphrasing it is not a copyright violation so long as the source is attributed as part of the citation or at the end of the article.

The best way to prevent close paraphrasing is to understand clearly when it is a problem, how to avoid it, and how to address it when it appears.