plagiarizer vs plagiariser

plagiarizer and plagiariser both are nouns.

Word	Noun	Adjective	Verb	Adverb
plagiarizer	Yes	No	No	No
plagiariser	Yes	No	No	No

As nouns, plagiarizer and plagiariser are synonyms defined as:

plagiarizer and plagiariser: someone who uses another person's words or ideas as if they were his own

Other synonyms of plagiarizer include literary pirate, pirate, plagiarist.

plagiarizer (noun)	plagiariser (noun)
someone who uses another person's words or ideas as if they were his own	someone who uses another person's words or ideas as if they were his own