criminologist vs specialist

criminologist and specialist both are nouns.

Word	Noun	Adjective	Verb	Adverb
criminologist	Yes	No	No	No
specialist	Yes	No	No	No

As nouns, specialist is a hypernym of criminologist; that is, specialist is a word with a broader meaning than criminologist:

criminologist: a specialist in criminology
specialist: an expert who is devoted to one occupation or branch of learning

Other hypernyms of criminologist include specialiser, specializer.

criminologist (noun)	specialist (noun)
a specialist in criminology	an expert who is devoted to one occupation or branch of learning
	practices one branch of medicine