psychologist vs scientist

psychologist and scientist both are nouns.

Word	Noun	Adjective	Verb	Adverb
psychologist	Yes	No	No	No
scientist	Yes	No	No	No

As nouns, scientist is a hypernym of psychologist; that is, scientist is a word with a broader meaning than psychologist:

psychologist (noun)	scientist (noun)
a scientist trained in psychology	a person with advanced knowledge of one or more sciences