urologist vs specialist

urologist and specialist both are nouns.

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

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

Other hypernyms of urologist include medical specialist.

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