self-plagiarism

noun

self-pla·​gia·​rism ˌself-ˈplā-jə-ˌri-zəm 

 also  -jē-ə-

plural self-plagiarisms

: the reuse of one's own words, ideas, or artistic expression (as in an essay) from preexisting material especially without acknowledgment of their earlier use

Borrowing your own words is a tricky issue. … Writers and publishers tend to rank self-plagiarism as a lesser offense than—what should we call it?—"real" plagiarism? Still, they mostly agree it's a no-no.

—Taylor Wofford

Word History

First Known Use

1833, in the meaning defined above