specialist vs specialize

specialist is a noun but specialize is not a noun.

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

specialist (noun)	specialize (noun)
an expert who is devoted to one occupation or branch of learning
practices one branch of medicine

specialist (verb)	specialize (verb)
	become more focused on an area of activity or field of study
	suit to a special purpose
	evolve so as to lead to a new species or develop in a way most suited to the environment
	be specific about
	devote oneself to a special area of work