Plagiarism of cited sources
Plagiarism can also mean passing off someone else's words as your own.
Even with proper credit, using full passages of another author's work is a copyright violation.
Except for very brief quotations that are essential to understanding a topic, copying content from copyrighted sources onto Wikipedia is against policy.
Instead, you should paraphrase the ideas and concepts you want to share on Wikipedia: present the information, phrased in a new way.