theorist vs theoriser

theorist and theoriser both are nouns.

Word	Noun	Adjective	Verb	Adverb
theorist	Yes	No	No	No
theoriser	Yes	No	No	No

As nouns, theorist and theoriser are synonyms defined as:

theorist and theoriser: someone who theorizes (especially in science or art)

Other synonyms of theorist include idealogue, theoretician, theorizer.

theorist (noun)	theoriser (noun)
someone who theorizes (especially in science or art)	someone who theorizes (especially in science or art)