plagiarist vs plagiariser

plagiarist and plagiariser both are nouns.

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

As nouns, plagiarist and plagiariser are synonyms defined as:

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

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

plagiarist (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