theoretician vs theorist

theoretician and theorist both are nouns.

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

As nouns, theoretician and theorist are synonyms defined as:

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

Other synonyms of theoretician include idealogue, theoriser, theorizer.

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