What's the noun for plagiarizers? Here's the word you're looking for.
plagiarism
(uncountable)Copying of another person's ideas, text, or other creative work, and presenting it as one's own, especially without permission; plagiarizing.
(uncountable) Text or other work resulting from this act.
“Perhaps Ben is glancing at Shakespeare, who, if accused of plagiary by an angry rival, would merely laugh.”
“Yet the problem does not resolve itself into the simple question whether Pandolfini or Alberti was the plagiary.”
“It may be that many a successful author has been a plagiarist, but no author ever succeeded because of his plagiary.”
plagiarist
One who plagiarizes; or purloins the words, writings, or ideas of another, and passes them off as his or her own, thus engaging in plagiarism; a literary thief; a plagiary.